By Fatskills Exam Guides Team — the exam nerds behind 28,500+ quizzes and 2.1M practice questions across 500+ global exams.
This guide covers the five A+ 220-1102 exam objectives related to Microsoft Windows OS troubleshooting, PC security, malware removal, mobile OS and application operational and security issues, and related topics.
These objectives may comprise 22 percent of the exam questions: - Core 2 (220-1102): Objective 3.1: Given a scenario, troubleshoot common Windows OS problems. - Core 2 (220-1102): Objective 3.2: Given a scenario, troubleshoot common personal computer (PC) security issues. - Core 2 (220-1102): Objective 3.3: Given a scenario, use best practice procedures for malware removal. - Core 2 (220-1102): Objective 3.4: Given a scenario, troubleshoot common mobile OS and application issues. - Core 2 (220-1102): Objective 3.5: Given a scenario, troubleshoot common mobile OS and application security issues. Given the widespread use of mobile devices, troubleshooting is now more than just solving problems with computers. However, many of the same principles apply, whether solving problems with computers, peripherals, or mobile devices: knowledge of products and operating system functions, understanding of the tools needed to diagnose and repair problems, and a determination to avoid data loss except when unavoidable.
Key Topics To Know (about Software Troubleshooting): Troubleshooting Common Windows OS Problems Common Symptoms BSOD Sluggish Performance Boot Problems Frequent Shutdowns Services Not Starting Application Crashes Low Memory Warnings USB Controller System Instability No OS Found Slow Profile Load Time Drift Common Troubleshooting Steps Rebuild Windows Profiles Troubleshooting Common PC Security Issues Common Symptoms Browser-Related Symptoms Best Practice Procedures for Malware Removal Troubleshoot Common Mobile OS and Application Issues Troubleshoot Common Mobile OS and Application Security Issues Security Concerns Android Package (APK) Source Developer Mode Root Access/Jailbreak Bootleg/Malicious Application Spoofing Common Symptoms Slow Data Speeds Leaked Personal Files/Data Data Transmission Over Limit Tools Factory Reset/Clean Install 220-1102: Objective 3.1: Given a scenario, troubleshoot common Windows OS problems. Troubleshooting is an essential skill for a PC technician. The capability to recognize and remediate OS issues starts with concepts covered in this section. Common Symptoms Windows OS has countless lines of code and several processes working simultaneously. Occasionally, some processes fail and cause problems for the whole system. Performance then is impacted in many possible ways, ranging from slow performance to system crashes. This section introduces some of the more common OS problems and tells how they can be recognized. BSOD Proprietary crash screens such as the Windows STOP error (blue screen of death [BSOD]) can be caused by operating system, application, or hardware errors. If Windows is configured to reboot when a STOP error occurs, the system will continuously reboot until the error is resolved. To leave a STOP error message onscreen until you decide to restart the system, clear the Automatically Restart check box in the System Failure setting in the Startup and Recovery section of Advanced System Properties. This is accessed via Control Panel System Advanced System settings. Under Startup and Recovery, select Settings. More details and depictions of this are highlighted in “Hardware and Network Troubleshooting.”
In Windows 10, STOP errors look like the example in the Figure below. The STOP error is listed by name.
A Windows 10 STOP Error Note: Regardless of when a STOP/BSOD error occurs, your system is halted by default. If the computer does not restart on its own, you must turn off the system and turn it back on. Before you do that, however, record the error message text and other information so that you can research the problem if it reoccurs. For more information, see the next section, “Causes of BSOD Errors.” Causes of BSOD Errors BSOD errors can be caused by any of the following: - Incompatible or defective hardware or software: Start the system in Safe Mode and uninstall the last hardware or software installed. Acquire updates before you reinstall the hardware or software. Exchange or test memory. Run SFC/scannow to check for problems with operating system files. - Registry problems: System Restore can also be used to revert the system and registry to an earlier state. - Viruses: Scan for viruses and remove any that are discovered. - Miscellaneous causes: Check the Windows Event Viewer and also check the system log. Research the BSOD with the Microsoft Support website.
Researching BSOD Causes and Solutions To determine the exact cause of a STOP error, note the number or name of the error (for example, “STOP 0x0000007B, HAL INITIALIZATION FAILED”) and look it up at the Microsoft support website: https://support.microsoft.com. When you search for the error, be sure to specify the version of Windows in use. Note: STOP errors are often referred to with a shortened version of the error code or by name. For example, the shortened version of a 0x0000007B error is 0x7B. Tip: Unfortunately, you can’t take a screen capture of a BSOD for printing because a BSOD completely shuts down Windows. In this situation, a digital camera or smartphone can be used to record the exact error message. The solution might involve one or more of the following changes to your system: - Changing the system registry. Sometimes you can download an automated registry repair tool to perform these changes for you. Whether you make the changes manually or automatically, back up the registry first. - Removing a newly added component. - Replacing components such as memory. - Upgrading an application. Sluggish Performance A slow system or sluggish performance can be caused by many issues in Windows. Table: Slow/Sluggish System Performance Causes and Solutions
Boot Problems Boot problems such as failure to boot can be caused by several issues, including incorrect boot order configuration in the BIOS/UEFI, corrupt or missing boot files, missing driver files, or even a failing CMOS battery. Windows uses the bootmgr and BCD files during the startup process. If these files are corrupted or missing, the corresponding error messages appear: - bootmgr is missing: This message appears if the bootmgr file is missing or corrupt. This black screen likely will also include the message “Press Ctrl+Alt+Del to Restart”; however, doing so probably will not fix the issue. - The Windows Boot Configuration Data file is missing required information: This message means either that the Windows Boot Manager (bootmgr) entry is not present in the Boot Configuration Data (BCD) store or that the Boot\BCD file on the active partition is damaged or missing. Additional information you might see on the screen includes File: \Boot\BCD and Status: 0xc0000034. A missing bootmgr file can be repaired in two ways: - Boot to the System Recovery options and select the Startup Repair option. This should automatically repair the system and require you to reboot. To access the options in Windows 10, locate the Advanced Startup Settings menu. - Boot to the System Recovery options and select the Command Prompt option. Type the bootrec /fixboot command, as shown in Figure below. Repairing BOOTMGR.exe from the Windows Recovery Environment’s Command Prompt For more about these steps, see https://support.microsoft.com/en-us/kb/2622803. To repair the BCD store, use this short process: Step 1. Boot to the System Recovery options and select the Startup Repair option. Windows should automatically repair the system and require you to reboot. If not, move on to the second step. Step 2. Boot to the System Recovery options and select the Command Prompt option. Type bootrec /rebuildbcd. - If the Bootrec.exe tool runs successfully, Windows presents you with an installation path for a Windows directory. To add the entry to the BCD store, type Yes. A confirmation message appears, indicating that the entry was added successfully. Restart the system. - If the Bootrec.exe tool can’t locate any missing Windows installations, you must remove the BCD store and then re-create it. To do this, type the following commands in the order shown here and press Enter after each command:
Bcdedit /export C:\BCD_Backup ren c:\boot\bcd bcd.old Bootrec /rebuildbcd
Frequent Shutdowns Continuous reboots can be caused by problems with the power supply or by a Windows or other operating system configuration setting: When the Power Good line to the motherboard carries a voltage that is too high or too low, the processor resets, shutting down the system and rebooting it. Test the power supply voltage levels; replace the power supply if Power Good tests out of specifications. Intermittent failures of other USB external devices or of internal devices can be caused by damaged data cables, power supplies or connectors, or ports. To troubleshoot these problems, follow these steps: Step 1. Shut down the device (and the computer, if the device is internal) and replace the data cable with a known-working replacement. If a USB device is plugged into a front-mounted USB port or a USB port on a card bracket, check the USB header cable connections to the motherboard. Step 2. Turn on the device or computer. Step 3. Test the device over time. If the device works correctly, the problem is solved. Step 4. If steps 1–3 did not resolve the problem, use the original data cable and try plugging it into a different internal or external port. Repeat steps 2–3. Step 5. Try steps 1–4 again, but this time use a replacement power connector or AC adapter. Step 6. When you find the defective component, the problem will stop. If the problem is not resolved with different data cables, connectors, or power supplies/AC adapters, the device itself needs to be replaced. Intermittent or frequent shutdowns are often a software issue. Updating drivers is a reliable fix. Also check the sleep mode settings in Windows 10, to make sure the computer is not simply going to sleep. Services Not Starting Remember that services are the numerous background applications running in Windows that perform the minor tasks that keep Windows 10 running. Dozens of services run in Windows 10, including even more extended services that support the Windows services. From time to time, one of these services might fail to load when booting. One common reason is that so many services are running that a non-Windows service interrupts a Windows service during the boot process. To view the available services, go to the Run command box (Windows+R) and type services.msc. From the Services menu, select the service that is experiencing a problem and check its status. If it is disabled, right-click the service and click Start to enable it. Figure 8-3 shows that the Data Sharing service in the Services console is disabled. Clicking Start on the General tab should enable it; if not, the Recovery tab (see Figure below) offers further options to restart the service. These options are available by right-clicking the service and selecting Properties. Services Manager
Other possible approaches include using Windows Recovery (WinRE) in the advanced setup menu. (This works in both Windows 10 and 11.) Three possible ways to access WinRE are as follows: - From the login screen, click Shutdown; then hold down the Shift key while selecting Restart. - Click Start Settings Update & Security Recovery. Under Advanced Startup, click Restart Now. - Boot to recovery media. Another option is to boot in Safe Mode and troubleshoot the Services. If problems persist, try running the System File Checker (from an elevated mode) and then reboot. System Restore (Settings Windows Update Advanced Options) can be used if the previous efforts fail. A last resort is to reset the PC (Settings Update and Security Recovery). Application Crashes Applications can misbehave or crash for a variety of reasons. Applications are written to work with operating system software, and well-written applications rarely have problems in that environment. Keep in mind, however, that OS software is constantly being updated for security and other reasons, and usually a lag occurs between the OS and application revisions. During that update lag, many possibilities can go wrong. Microsoft is constantly updating Windows 10 with code and patches that work with specific applications. These patches do not necessarily install automatically. You can customize these updates in Windows Update settings. To access these settings in Windows 10, go to Start Settings Update & Security. If needed, the Advanced Options tab is available. Also available from the Update and Security page in Settings is the Troubleshoot tool, which offers a way for Windows 10 to self-diagnose and repair problems. To access these settings in Windows 10, go to Start Settings Update & Security Troubleshoot. Options for managing how to run Troubleshoot automatically are available in the drop-down list. If you encounter application errors, also check with the application developers to see if updates are available. Software “patches” are small updates that can fix known problems until a full version update is available. If patches are not available and the software is essential to the business, you might need to roll back the OS update to improve performance. Of course, updates happen for a reason; if security issues arise from rolling back an update, be sure to address those in some other way, if possible. Drivers for peripheral devices and video and graphics cards can be another source of application issues. Windows Updates usually include the drivers, but the manufacturers have them as well. Uninstalling a driver and then replacing it can often solve a problem. Low Memory Warnings If Windows issues a warning stating “Your computer is low on memory,” the likely cause is that not enough memory resources exist for all the tasks the computer is trying to perform. The computer might be under-resourced (see “Hardware,” for more on adding RAM) or some application (or even a virus) might be demanding more processing power than should be allowed.
Figure below depicts the following steps that address low memory warnings by adjusting allotted virtual memory. Virtual Memory
The first step in addressing this warning is to visit the Task Manager and see where the resources are being allotted. If unused or unnecessary applications are open and are demanding memory space and CPU time, shut them down so that you can free up resources. As applications are closed, more memory becomes available. If an unrecognized app is using memory, research the app or service to see if it is necessary. If no information is available, scanning for a virus or malware is a good idea. Another option is to increase virtual memory, which means assigning some hard drive space to perform as RAM. To increase virtual memory, follow these steps: Step 1. Press Windows+X and then select System. Step 2. Select Advanced System Settings. This opens the System Properties page. Step 3. Select the Advanced tab and choose Settings under the Performance tab to open the Performance Options window. Step 4. Choose the Advanced tab and select Change under Virtual Memory to access the allocation settings. USB Controller The warning “Not Enough USB Controller Resources” indicates that too many USB devices (or, more likely hubs) are trying to access a limited number of endpoints in the USB controller. This is more common with USB 3.0 devices than USB 2.0 devices because, in greatly simplified terms, USB 3.0 can demand more resources. The following are quick fixes for this issue: - Disconnect unnecessary hubs or devices from the computer to free up endpoints in the controller. - If possible, move some devices or external hubs from USB 3.0 to USB 2.0 ports (or simply use a USB 2.0 cable from the computer to a USB hub). This should free up some access to the controller. - Add a USB host controller in a PCIe slot. - Reinstall the Universal Serial Bus Host Controllers. For a deeper dive into how to reinstall USB host controllers, see https://thegeekpage.com/not-enough-usb-controller-resources/fix. To troubleshoot USB problems, follow these steps: Step 1. Shut down the device (and the computer, if the device is internal) and replace the data cable with a known-working replacement. If a USB device is plugged into a front-mounted USB port or a USB port on a card bracket, check the USB header cable connections to the motherboard. Step 2. Turn on the device or computer. Step 3. Test the device over time. If the device works correctly, the problem is solved. Step 4. If steps 1–3 did not resolve the problem, use the original data cable and try plugging it into a different internal or external port. Repeat steps 2–3. Step 5. Try steps 1–4 again, but this time use a replacement power connector or AC adapter. Step 6. When you find the defective component, the problem will stop. If the problem is not resolved with different data cables, connectors, or power supplies/AC adapters, the device itself needs to be replaced. System Instability The underlying issues that cause system instability could be the same or similar to the issues mentioned in the previous sections. However, if the PC runs slowly or is intermittently sluggish, and if additional RAM (or page file management), startup program management, and updates have not resolved the issue, you can take a few more steps: - Free up disk space in Storage Settings (Settings System Storage). - Pause synching. Synchronization of OneDrive, Dropbox, or other cloud storage can intermittently use up resources, causing slow traffic and sluggish loading of apps. Try temporarily pausing the synchronization and check for performance improvement. - Check/scan for virus or malware problems. - Recent updates and changes might be the issue. Restoring from a System Restore point can remove troublesome programs without removing your personal files. No OS Found If an operating system cannot be located, boot into the BIOS/UEFI and check that the computer is looking in the correct place for the OS. The drive hosting the OS should be in the first option to boot. Loose cables are another common problem that can cause a boot to fail. If the boot option settings are correct in the BIOS/UEFI, check the cables; sometimes cables look connected but are not seated properly. Resetting the BIOS/UEFI is also an option. The BIOS?UEFI menu has options for restoring defaults. Slow Profile Load A user profile contains personalized settings for devices such as the mouse and keyboard, Windows-based applications, and desktop files and settings. Sometimes a user notices that one profile loads much more slowly than other profiles. One reason for a slow-loading profile is that many large files and folders are stored on the desktop and need to be loaded as part of the profile. Storing these large files in My Computer or another drive reduces the load time. To check the size of a user profile, use the Run dialog box or the search tool and enter sysdm.cpl. This brings up the System Properties menu in the figure below. Checking User Profiles From the System Properties menu, select the Advanced tab and then select Settings under User Profiles. The User Profiles information displays as shown in the second window of the figure above. Note: One profile is much larger than the others. In this case, you should suggest to this user that cleaning up the desktop will likely avoid slow profile issues. Time Drift Time drift occurs when the clock for one computer or server does not agree with the clocks of other computers it interacts with. This can cause several issues that can be hard to detect. For example, event logs used to troubleshoot can have the wrong time stamps, and other computers or servers, both local or on the Web, can experience secure transaction issues or authentication issues. The easy fix here is to set a computer’s time to align with the time used by the National Institute of Standards and Technology (NIST), found at www.time.gov. This site even provides a calculation of the difference between the device’s clock and the NIST time. Use this clock to reset the time on the computer. A computer network should have all its devices running on the same time. This can be done by establishing a clock server in a network and running NTP (the Network Time Protocol) on all devices. Time settings, as well as the option to manually synchronize the clock, are found under Settings System Date & Time, as the figure shows. Note that, in the example, the source for the time setting is the server located at http://time.windows.com. Time Settings Common Troubleshooting Steps This section lists common Windows OS troubleshooting steps that have been described throughout the book. The list starts with simple first steps and progresses through increasingly complex steps. You should be familiar with these steps for the examples you might see on the A+ exam. - Reboot: Rebooting is always a good first step, especially if the device has been running for an extended time. - Restart services: From the Run menu, type either servces.msc or services in the search bar and then open the Services app. Select the application and stop or restart as needed. - Uninstall/reinstall/update applications: Go to the Microsoft Store app, select Account, and then select App Updates. The store can update apps automatically. - Add resources: Always remember, few actions can improve a PC’s performance more substantially than adding more RAM. - Verify requirements: New versions of software and upgrades to hardware can make current specifications obsolete. RAM, storage, and power supply issues can creep into an upgraded system. - Perform a system file check: Select Windows+X/PowerShell (Admin). Type sfc /scannow (include the space after sfc). - Repair Windows: Rebooting while pressing F11 (on most machines) brings up Windows 10 Advanced Starting Options. Select Troubleshoot Advanced Options Startup Repair. - Run Windows Recovery (WinRE): Click Start Settings Update & Security Recovery. Under Advanced Startup, click Restart Now. - Perform a System Restore: Pressing Reboot+F11 (on most machines) brings up Windows 10 Advanced Starting Options. Select Troubleshoot Advanced Options System Restore. - Reimage: Pressing Reboot+F11 (on most machines) brings up Windows 10 Advanced Starting Options. Select Troubleshoot Advanced Options System Image Recovery. - Roll back updates: Reboot+F11 (on most machines) brings up Windows 10 Advanced Starting Options. Select Troubleshoot Advanced Options Uninstall Updates. Rebuild Windows Profiles User profiles contain desktop backgrounds and files, icons, and other personal data that can bloat a profile and cause it to load slowly when booting. If other profiles load quickly, too much data might be the problem. Manage the profile data by reducing data in the profile or removing it. Note: Removing a profile is not possible while working inside it. Instead, you must access a different profile (or create another one, if necessary). It is possible to delete a profile without deleting a user account. When you have finished deleting a profile, restarting generates a new profile for the user account.
The steps for rebuilding a Windows profile are as follows: Step 1. To delete a user profile, use the Run dialog box or the search tool and enter sysdm.cpl. This brings up the System Properties menu shown in Figure 8-5. Step 2. From the System Properties menu, select the Advanced tab and then choose Settings under User Profiles. The User Profiles information displays, as in the second window of Figure 8-5. Step 3. Select the profile and then click the Delete button. Step 4. In the Registry Editor (regedit in the search bar), delete the user profile found at the end of the following path: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\ProfileList. Step 5. Reboot.
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