I am running Windows 10 under Parallels 11.1.3 on a Macbook Pro running El Capitan 10.11.6. Normally, I configure backup by checking the box "Do not backup with time machine". I would periodically (approximately monthly) uncheck the box and create a backup of Windows 10.pvm on time machine. I would then check the box again afterwards. I have done this since I have had the MAC (4 years) and when the time machine hard drive filled up, I would erase the Windows 10.pvm files from time machine to free up disk space. I have restored old Windows.pvm files several times this way over the years after the occasional corruption or virus infection. In January, I cleaned up time machine by deleting all the old Windows 10.pvm files from time machine. I even created a secondary backup file by renaming the PVM file before back up and then restoring the name afterwards. Time machine would then contain 2 pvm backups with different names. Since January, the backups made started disappearing from time machine. I made a backup last month and checked the do not back up box afterwards. Before I went to make another backup today, I looked in time machine and the previous backup file had disappeared. None of the PVM files I previously backed up were there. I checked the directory on the time machine drive and the files are not there. The last file was definitely on the disk after I made the last backup. I have lost 3 backups this year. Why this behavior change? I'm thinking that now when I change the setting back to "do not back up with time machine", time machine erases the old backups. I want to keep periodic backups of the pvm file but this strategy no longer works. Any ideas?
