Error on TimeMachine (unable to backup) Until the mid-april I was used Time Machine with no problem but now no backup is possible (Time  Machine starts, finds the drive, prepares the copy and stops). In the log I have found the following errors:

2019-04-30 14:22:38Error] Failed to mount APFS snapshot with name 'com.apple.TimeMachine.2019-04-10-174518' on volume '/' at mountpoint: '/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/XXX/2019-04-10-174518/Macintosh HD', error: Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"
2019-04-30 14:22:38Error] Failed to mount reference snapshot: com.apple.TimeMachine.2019-04-10-174518 source: Macintosh HD


Time Machine tries to find an old local snapshot which does not exist anymore (sudo tmutil localsnapshot gives me only the last one Created local snapshot with date: 2019-04-30-143219). On my drive I can see that the last snapshot (sudo tmutil listbackups) is 2019-04-10-181153. So I don't understand what is  this issue.

My MBP is running on MacOs Mojave (10.14.2)
I think I have the same problem today. I resolved my problem by rebooting to macOS Recovery (turn off your Mac and press ⌘+R during while pressing power button), and use disk utility to check(First Aid) my boot drive.