Is there a way to delete one file from past TimeMachine backups?

Paulfletcher wrote:

I'm on OS 10.13.6. I have a external drive for TimeMachine. I want to delete one file from the TimeMachine backup of a few backups ago. (The file isn't on later backups.) I would delete the whole back done on that date but there are other writings I don't want to lose on that date's backup. Are the writings still on my main computer even though TimeMachine backed them up? If so, then I could delete the entire backup on that date and still have the files that were backed up on my main MacBook Pro.

I would not mess with the TM database. No.

You interface with the TM through the interface only

The main advantage of TM is that it creates recursive backups—enabling you to restore a specific file or the entire drive— from a certain point in time.

restore items backed up with Time Machine

https://support.apple.com/guide/mac-help/restore-files-mh11422/mac

Restore items backed up with Time Machine on Mac - Apple ...

There used to be a way to do it by going into the Time Machine, right clicking on the "Today" version of the file and a "delete all copies" or similar command was available on right-clicking the file. I can't see that option on my Time Machine today, but that might because not all the discs are connected (I have some offsite backups). If you try this (click TM in menu bar and then click Browse and note that it might take a long time for all the bakcups to become visible) and the option is available then it might be OK to use it, but I'd need a pretty serious reason to mess about with mine like this. If you do, then you must immediately verify the backup afterwards.

My advice, however, echoes leroydouglas - leave it alone unless deleting this file is more important than losing your backup. If it's that important (e.g. legal requirement) then as a minimum I'd create a new, separate backup and then delete the backup with the file you want to delete. Otherwise you run the risk of getting some months or years down the line and needing to recover something equally important only to find out that your backup is useless.