Apple is resetting the iTunes Match beta on Monday at 9am, according to an email sent to developers late on Friday night. Developers’ music libraries will be erased and the match process will have to begin again.
The email from Apple says:
To continue to improve the overall quality and reliability of iTunes Match, it has become necessary to delete all current iCloud libraries.
All iCloud libraries will be deleted on Monday, September 26th at 9AM PDT. To prepare, please turn off iTunes Match on all of your computers and iOS devices. On your computer, choose Store > Turn off iTunes Match. On your iOS device, tap Settings > Music, then turn off iTunes Match.
The email says local songs will not be effected. But everyone using the beta should back up just in case. Fingers crossed no iTunes libraries are zapped on Monday.