This content is part of the Essential Guide: Windows 10 how-to guide

How to swat away five common Windows 10 bugs

Windows 10 has as many problems as any other OS before it, including startup speed issues, Windows defender failures, device driver issues and more.

Windows 10 is not perfect. Since its release in July 2015, bugs and issues have popped up in the operating system all over the place.

Early on, many users reported problems with Cortana. Some users ran into a related problem where the OS displayed a "Crucial error: Start Menu and Cortana aren't working" message, which rendered the entire OS useless. Although this turned out to be a Dropbox issue and not something that arose from Windows or Cortana directly, several other Windows 10 bugs cause downtime and loss of productivity. Users and IT administrators must find fixes or workarounds.

Device drivers be damned

Incompatible device drivers still account for a lot of Windows 10 issues, especially with graphics. Some users have reported computers stop responding, the monitor flickers and a "Display driver stopped responding and has recovered" message appears. To solve this, reboot and then open Device Manager. Right click the graphics driver and select "Update Driver Software." If that doesn't work, return to Device Manager, right-click the driver, select "Uninstall" and follow the prompts. Then click the "Scan for hardware changes" icon on the Device Manager toolbar. You can also try a third-party utility such as SlimDrivers or Driver Talent, which inventory the drivers on a computer, flag ones that have new drivers available and let you pick which ones to update.

If the computer has a graphics processing unit installed, you may have to increase the processing time by adjusting the Timeout Detection and Recovery registry value. Remember to back up the registry before making any changes.

In the Registry Editor, browse to and then click HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers, then click "New" in the Edit menu. From the drop-down menu, select QWORD as the registry value for 64-bit Windows or DWORD for 32-bit Windows. Then enter "TdrDelay" for the name and press Enter. Double-click "TdrDelay," enter 8 in the Value data field and click OK. Reboot and test it out.

Windows 10 glitches also come from networking connection issues. It's good to keep a USB dongle for Gigabit Ethernet on machines with Killer NICs because Windows isn't good at recognizing these network interfaces. When you boot into Windows 10 after an upgrade or clean install on a PC with a Killer NIC, you won't be able to access the network. With a plug-in USB device as a temporary replacement, you can access any number of download resources to find a working driver for your Killer NIC -- or use another machine to do likewise.

For newer Killer NIC models (E2200/2400, Wireless 1525/1535), the Rivet Networks download page is a good driver source; for older models Softpedia and driver download services are your best bet.

Windows Defender stopped working

Windows Defender, Microsoft's built-in antispyware program, leads to Windows 10 problems because it stops running after the Threshold 2 update. If the computer runs another antimalware package such as Norton or Kaspersky, it's normal for Windows Defender to be turned off. If that's not the case and you need Windows Defender, you may need to add a key to the Windows registry to enable it. provides an executable that safely creates and sets the correct key in the registry in the HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender hive. Once you update the registry, you should be able to click the Start now button in Windows Defender to get it running.

No more zippy startup

When you first use Windows 10, the system boots quickly, even with Windows 8.1 hardware and software. Then things slow down -- a lot. Even with "Turn on fast startup" selected in Power Options and a curated list of services that start automatically, it can still take several minutes for a system to get up and running from a cold boot or restart.

The best fix is to add a solid-state drive (SSD) to the computer as its boot drive. Although it's possible to move an OS from one drive to another with the right tools, the best method is to back up all the data --and check it to make sure the backup is good -- and perform a clean install on the SSD drive. Create an image backup first, then create recovery media, back up data files to a USB drive for easy transfer back to the original computer, and make sure you have all product keys. Once the clean install is complete, use the former boot drive -- which is now either D or E -- as the data drive. You will be surprised at how quickly the system boots. It can go from a five-minute boot to about 15 seconds.

Additionally, some users noticed their custom display settings were reset after the Threshold 2 update. Other users reported their default programs and settings changed, and their system restore points were deleted. Unfortunately, there's no good fix for this one. Microsoft is working on the next major update to Windows 10 which should be released in Q2 2016.

Toolbox tips

To prevent Windows 10 bugs, before a major update, remove unnecessary temporary files and system files with Disk Cleanup. The system files in particular could hamper an update.

When faced with other system-related Windows 10 problems, run the System File Checker tool to search for damaged, corrupt or missing system files. This command-line tool scans and evaluates protected Windows system files, and tries to replace files where possible. The sfc /scannow command requires administrative privileges, and may take some time to complete depending on the extent of system damage.

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