With Windows 10 Build 9926 already being consumed by Windows Insiders everywhere, it's important to understand what is actually being offered, but even more important to know what to expect. Most who are downloading and installing the new Build are doing so due to being enamored with the promise of new features thanks to the homerun the company hit during its recent Windows 10 event. Despite Microsoft taking a break from delivering new Builds during the month of December, it's clear the company hasn't taken a development break. Windows 10 Build 9926 presents a huge number of improvements, additions, and changes from previous Builds.

But, there are gotchas. Ahead of the release of Build 9926, Windows Insider chief, Gabe Aul, delivered a blog post to give early warning of issues that Microsoft already expects to cause problems for testers (included below). But, since then, even more gotchas have been identified by those already running the Build. So, I'd like to keep a running list so we can hopefully help each other through this process.

Here goes...

What we know

Delivered by Microsoft as a sort of known issues doc:

• 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 pixilation.
• 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.
• In-app purchase is not available for apps downloaded through the Store Beta.

What we've heard

• Windows 10 can't be installed on a compressed drive
• Surface Pro 3 users will experience video problems (covered HERE with fix, and HERE with additional steps)
• There are two Store icons now. One linked to the old store and one linked to the new, Beta store. If you install your apps from the beta version of the store, your app purchases may not be recognized.
• You can no longer drag tiles from the new Start Menu to the desktop.
• The new Start Menu can only be maximized and minimized, it cannot be resized. However a registry edit can fix it.
• Cortana is limited to U.S. and English
• Once Build 9926 is installed, there's an immediate performance hit due to a OneDrive resynch
• Continuum works for most, but not all, hybrid devices, even if manually enacted
• Some included apps may not launch or might hang on the splash screen. Here's a fix: Fixing Windows 10 Apps that Won't Launch or that Hang on the App's Splash Screen
• Sleep not working for some Lenovo systems.
• Windows crashes while browsing the web – Issue with Sophos 10.3 - submitted by Adam Munns

I'm keeping a close eye on newly reported problems and will post those here, along with solutions when they are found. And, of course, I'll be reporting any additional problems I find personally. If you've experienced some strange problems not listed here after installing Windows 10 Build 9926, let me know in the comments, over Twitter, or even use my email address to contact me directly.