Microsoft recently released an update (KB3020114) for the Windows 10 Technical Preview to fix an issue with frequent Explorer.exe crashes. These fixes help you to keep your Windows 10 Technical Preview usable through the end of the year when a full new Windows 10 Technical Preview build is released until early 2015.
Unfortunately, many of us have ended with a problem installing KB3020114 update, causing the install to fail.
The issue occurs due to 2 underlying bugs:
- In build 9879 we introduced some new System Compression code that systems with SSDs can take advantage of to reduce disk usage by the OS. In some cases the logic for low-space detection gets inverted, and we compress automatically as a background operation.
- On PCs have had system compression enabled, an additional bug with how the filesystem tracks deletes caused the installer to think that the temp files failed to extract correctly, so the installer fails because it thinks it cannot complete.
For the short term, anyone affected by this can get past it with the following workaround:
- Restart your PC
- Open CMD.exe as an Administrator and run: compact /u /exe /s:%windir%\winsxs\filemaps
- Immediately afterwards run Windows Update and Check for Updates
- Install KB 3020114
- Restart when prompted
Windows Team need to fix the 2 underlying issues above, and make sure that no additional problems prevent hotfix installs in the upcoming release of Windows 10. They are working on this but it will take a bit more time to ensure we got it right.
The good news is that people are helping Windows Team to find and fix these issues much faster than in the past, which means that the final product will be higher quality as well as having features shaped by our feedback.