Page 3 902 Software Troubleshooting Study Guide for the CompTIA® A+ exam

Mobile OS and App Issues

Portable devices are becoming more common in the workplace, so you will need to become familiar with the following items related to support of these devices.

  • dim display: For mobile devices with dim displays, try to adjust the screen brightness, assuming you can see the screen in a darkened room. For Android devices, go to Settings > Display > Brightness Level. For Apple IOS, go to Settings > Displays and Brightness. If that doesn’t work, the entire display must be replaced.

  • intermittent wireless: Determine the distance to the wireless access point and determine if that can be modified. Verify WiFi connections on the device.

  • no wireless connectivity: Verify the WiFi settings are correct. Perform a hard reset on the specific device, if necessary.

  • no Bluetooth connectivity: Check bluetooth configuration parameters: unpair and pair the device. Perform a hard reset on the specific device, if necessary.

  • cannot broadcast to external monitor: Devices vary, so check the setup for the remote device. Verify network functionality: are they on the same subnet?

  • touchscreen non-responsive: If the device is completely blank, you may be able to get the power option to appear on an Apple by holding down the Power button, then power off. Hold the Power button and the Home button simultaneously for 10 seconds to perform a hard reset of the device.

  • apps not loading: Reboot the device and retry the application. Also, try to perform a hard reset.

  • slow performance: You may have to administratively stop the application in question, then restart. On an iPhone, double-tap home and slide the application out of memory. For Android, go to Settings > Apps, and then select the app and tap Force Stop.

  • unable to decrypt email: To decrypt email, mobile keys are necessary. You may have to contact the sender and exchange keys.

  • extremely short battery life: The most likely cause of short battery life is that the battery may need to be replaced, or that there are too many applications running consecutively.

  • overheating: If a cell phone appears to be running too hot, check to see which application is using the most CPU. This and recharging a battery are common causes for the heat generated in a cell phone.

  • frozen system: To bring a mobile device out of a frozen state, you should run a hard reset of the device. On IOS, press and hold the Home and Power buttons simultaneously for 10 seconds. For an Android, press and hold the Power, Volume, and Home buttons simultaneously for 10 seconds.

  • no sound from speakers: Verify that the volume control is set to the proper level. Test the internal speaker by plugging in an earphone. Perform a factory reset on the device.

  • inaccurate touch screen response: Perform a hard reset of the device. If that fails, replace the digitizer.

  • system lockout: On an Apple iOS device, ten failed login attempts will cause the device to erase everything internally. This feature is the default setting, but can be disabled. On an Android, use the Google account associated with the device to unlock the device.


The tools needed to maintain mobile devices are listed below. Be sure you can identify the function of each.

  • hard reset: To perform a hard reset on an IOS device, press and hold the Power and Home buttons simultaneously for 10 seconds. For the Samsung Galaxy, power off, press Volume Up + Home + Power, wipe factory reset.

  • soft reset: On an Apple iPhone, press and hold sleep/wake and Home button for 10 seconds. On an Android, hold the Volume Up + Home + Power.

  • close running applications: To close a running application in an Android, tap the Recent Application icon, and then select Close All. On an Apple IOS, double-click Home button, find application, and then close.

  • reset to factory default: On an Android, power off the device, hold the Volume Up and Power buttons until power comes on, and then Volume Down to select factory reset. On an Apple IOS, use ITunes to reset to factory default.

  • adjust configurations/settings: On an Android, select Settings. From Settings, you can set: Wireless and networks, Phone, Personal, and System settings. On an Apple iPhone, all configurations and settings are available under Settings.

  • uninstall/reinstall apps: On an Android phone, locate and long-tap the application to delete and then drag to uninstall button. On an Apple iPhone, hold the Home button, find the app you want to delete. Press and hold it, momentarily.

  • force stop: Force stop will kill applications running on a mobile device. On an Android, touch Apps under Settings, select the app, and then select Stop. On an Apple iPhone, double-click on Home, then swipe the app to force it to stop.

Mobile OS and App Security Issues

Because mobile devices are portable, they are more easily misplaced, so securing data on one is an important consideration.


The following are the symptoms you need to be familiar with when dealing with mobile devices.

  • signal drop/weak signal: Since all communications from a mobile device are done wirelessly, it is important to consider security. Avoid public WiFi networks and consider VPN for high security communications.

  • power drain: Portable devices have a finite amount of available power. If you find the battery is constantly running low, you may want to see what other applications are currently running and eliminate them if not vital. Also, many portable devices have batteries that are getting old and may need to be replaced.

  • slow data speeds: The available amount of bandwidth (speed) from a cell tower diminishes as distance increased. To verify the theoretical maximum throughput, you may want to utilize a third-party application that will verify the amount of bandwidth available.

  • unintended WiFi connection: If you feel there are unauthorized connections to your WiFi, you may want to investigate using a network analyzer to see how traffic is being handled.

  • unintended Bluetooth pairing: It is possible your Bluetooth is paired with an unintended user. Check your mobile device to see what is actually paired with you and consider disabling Bluetooth when you’re not using it.

  • leaked personal files/data: Mobile devices are susceptible to unauthorized access through malicious software. When infected, personal files and data can be leaked to unauthorized users. Consider an anti-malware scan for mobile devices, much the same as for PCs and laptops. If applications that were not installed appear, consider a factory reset and clean installation.

  • data transmission overlimit: Depending on your carrier, the amount of data you use is limited by your contract. When you near the limited amount, the carrier usually notifies you. If you are unaware of this and go over your data limit, your carrier may disable data usage.

  • unauthorized account access: Be certain you are connecting through a trusted WiFi network so you know exactly what is being sent.

  • unauthorized root access: Android phones are based on Linux and a user needs root permissions to perform certain actions. Always acquire applications from a trusted source to prevent unauthorized access to the root account.

  • unauthorized location tracking: To prevent unauthorized GPS tracking on a mobile phone, the user needs to disable the tracking feature of the phone.

  • unauthorized camera/microphone activation: Cameras and microphones on mobile devices are susceptible to hacking, allowing access to these devices. To prevent this, as with most cases of mobile hacking, users need to be vigilant when it comes to acquiring applications. Only download applications from a trusted site.

  • high resource utilization: One cause of shortened battery life could be from having too many applications running at any one time or an excessive amount of network utilization. Higher than normal resource utilization could also be caused by malicious software running on the device.


Tools utilized by mobile devices are similar to the ones used by desktop and laptop devices. Here are important ones to know about.

  • anti-malware: Any of the symptoms found in desktop and laptop systems can also occur in mobile devices. Anti-malware software is available from multiple vendors for use on mobile devices.

  • app-scanner: Prior to loading applications onto a mobile device, you may want to check and verify that it is free of any form of malware. There is application-scanning software that you can use to verify software before loading it onto a mobile device.

  • factory reset/clean install: To completely remove any malicious software from mobile devices, you can perform a factory reset then perform a clean install. On an Android, power down the device, hold Volume Up and Power until power comes on, then Volume Down to select factory reset. On an Apple iOS, use iTunes to reset to factory default.

  • uninstall/reinstall apps: To remove applications on an Android mobile device, locate and long-tap the application, and drag to the uninstall button. On an Apple iPhone, hold the Home button, find the app you want to delete, and press it and hold momentarily. After applications have been removed, a fresh copy can be reinstalled.

  • WiFi analyzer: A WiFi analyzer allows you or an unauthorized user to view traffic on a WiFi network.

  • force stop: Force stop will allow you to kill applications running on a mobile device. On an Android, touch Apps under Settings, select the app, and select Stop. On an Apple iPhone, double-click on Home, then swipe the app to force it to stop.

  • cell tower analyzer: A cell tower analyzer allows you to view the amount of traffic on a cell site and give you an estimate of how much speed you can expect to get on the network.

  • backup/restore: Mobile devices support many various methods of performing backup and restoring your device. Most of these are cloud-based services provided by the vendor. Apple devices include iTunes and iCloud. Android devices utilize Google Sync. Other cloud-based solutions are available from Dropbox, OneDrive, and Carbonite, to name a few.