Backup failed with cryptic message

Error log:


08:40:43 Database backup: Compressing the backup
08:59:40 Database backup: Failed
08:59:40 MailClient.Scheduler.SchedulerException: Database backup task failed: Could not find a part of the path ‘C:\Users(placeholder)\AppData\Local\Temp\eM Client temporary files\zgxcj3fr\Archive\conversations.dat’.
—> System.IO.DirectoryNotFoundException: Could not find a part of the path ‘C:\Users(placeholder)\AppData\Local\Temp\eM Client temporary files\zgxcj3fr\Archive\conversations.dat’.
at System.IO.FileSystem.DeleteFile(String fullPath)
at MailClient.Scheduler.Tasks.BackupTask.PerformCompression(BackupCompressionTool zip, CancellationToken token, String tempDirectory)
at MailClient.Scheduler.Tasks.BackupTask.DoWork(IWin32Window owner, CancellationToken token, IScheduler scheduler, ReportProgress progressReporter)
— End of inner exception stack trace —
at MailClient.Scheduler.Tasks.BackupTask.DoWork(IWin32Window owner, CancellationToken token, IScheduler scheduler, ReportProgress progressReporter)
at MailClient.Scheduler.Scheduler.<>c__DisplayClass14_0.b__0(Object state)
GUIStatus_Exception_Reported = True


Please advise.

Remaining disk space: over 25 GB (throughout backup process)

Thanks!