Time Machine error - Console poiting to an error with backupd

2012 MacBookPro 15" running 10.15.7

I have been using Time machine for years without problems but am now getting an error. I plug in the drive, it starts backing up, and after about 10 minutes I get the error "An error occurred while copying files." I checked the console and found this error:

Failed to bootstrap path: path = /System/Library/CoreServices/backupd.bundle/Contents/Resources/backupd, error = 2: No such file or directory

I have reformatted this drive multiple times but it doesn't solve the problem. I have also tried a second hard drive and it gets the same error.