If you use apps from the Mac App Store, you may be experiencing a problem that affected many users earlier this week. Some people had to delete all their apps and reinstall them.
These users found that their downloaded apps from the App Store were broken. The cause of the glitch is something of a mystery.
However, it may have been the result of a lapse in a five-year-old security certificate. Mac uses that certificate to protect users' privacy. There appears to be a simple solution: rebooting your device.
Apple has issued an updated security certificate, which should solve the problem. However, some Mac App Store users continue to report problems.
The problem was first reported by Mac and iOS developer Paul Haddad. He took his message to Twitter, as did angry Mac App Store users. (See photos.)
Have you been having problems accessing the Mac App Store? Let us know in comments.