Now that Windows 10 build 10061 has arrived, here are some of the known bugs you'll encounter

With the release of Windows 10 build 10061, "Insiders" should see marked improvements and additional features to Microsoft's latest technical preview. While being able to experience these improvements and additions first is always nice, there are also issues that user might happen to experience being a "fast ring" participant. Naturally, Microsoft has disclosed a number of known issues with the recently released build that are detailed verbatim below.

• We know this one will be a bit painful but there is a bug with this build in which Win32 (desktop) apps won’t launch from the Start menu. The workaround is to use search to find and launch these apps and pin them to your taskbar for quick access.
• The Windows Store Beta (grey tile) and Project Spartan get unpinned after upgrading. You can re-pin them to your Taskbar from All apps on your Start menu.
• The version of the Mail and Calendar apps included in this build (17.4008.42281.0) have a known issue that causes every typed letter to appear twice. Which might be funny if it weren’t so irritating. We have fixed this issue with updated versions of the apps (17.4016.42291.0) available in the Windows Store Beta (grey tile). If you don’t open the Mail and Calendar apps within the first 15 minutes after logging in to your device for the first time after upgrading and your device is connected to the Internet, the apps should update automatically. You can also go into the Store Beta and check for updates manually at any time.
• Cortana will highlight things it will be able to help users with, but some of these features are not yet implemented and we are working to deliver them soon.
• There is a known issue where you might see a black screen with only your mouse cursor during login/logout. We have a fix for this coming via WU.
• Downloading music in the Xbox Music and Music Preview apps is currently broken. We also have a fix for this coming via WU.
• When you minimize an app playing audio, it may stop playing once its minimized.
• In Project Spartan, no selection highlight appears when selecting text in the address box. You can right click in the address box to cut/copy/paste and it will work as expected. We also have a fix for this coming via WU.
• Magnifier does not work when you put it into docked mode. We will also have a fix for this coming via WU.

While these issues will be present for those on the fast ring, slow ring users should be able to download a new build of Windows 10 once the experience has been made more stable. Look for more coverage on Windows 10 build 10061 in the next few days.

Source: Microsoft