Here's a list of known issues with the Windows 10 January Technical Preview

If you're taking the leap and installing todays Windows 10 Technical Preview build 9926, you're bound to encounter some bugs. For your convenience, however, Microsoft has gone ahead and created a list of known issues as of the release of build 9926.

Here's a breakdown of the known issues from Microsoft:

• After installing this build, you may see a boot selection menu each time you reboot your PC. This is because a bug where a second boot option is persisted to uninstall the Windows 10 Technical Preview and roll back to the previous OS installed. When you get to this screen, if you do nothing it will automatically boot to the Windows 10 Technical Preview within 30 seconds by default or you can choose it on your own. Don't worry, this behavior is only temporary.
• Xbox Live enabled games that require sign-in will not launch correctly. If you see the below dialog box the game requires Xbox Live sign-in. A fix for this will be distributed via WU shortly after the release of Build 9926.
• Battery icon shows on lock screen of PCs without batteries.
• Tiles on the Start menu show truncated app names (such as the Windows Feedback app).
• Remote Desktop has some painting issues that result in tiled pixelation.
• Connected Standby enabled devices like Surface Pro 3 may experience shorter than expected battery life.
• In Cortana, reminders can't be edited and more complex reminders might not get created. The first reminder you create in Cortana in this build might not pop up, but subsequent ones will. Completed reminders also don't move to the History page in Cortana's Notebook.
• The Music app will disappear if minimized within 16 seconds of launch. Just leave it in the foreground for 20 seconds or so and it should work just fine.
• Occasionally, the Start Menu is improperly registered and will fail to launch.

If you experience any of the above problems, don't fret! Microsoft notes that some of these issues may be fixed in further updates after release, while others may be patched up in future builds.

Source: Microsoft