On Windows, Ableton creates a new folder for each version in C:\Users\[USER]\AppData\Roaming\Ableton.

I currently have various folder such as 9.5, 9.6, 9.6.1, 9.6.2 etc. When I check these they report in right click properties that they are taking up 6GB or so. I have no idea what is the data as there is nothing obvious in them, and each new version folder seems to increase in size. You can find these folder easily by opening Windows Explorer and typing %APPDATA% into the folder name box. You will see the Ableton folder in there as %APPDATA% takes you straight to the roaming folder.

Is it safe to delete all of the previous versions, only keeping the folder for the current version that you are on? I assume it is, but wanted to double check before being too hasty!

 

Sure. I have, and do, delete previous versions' data. However, I recommend you keep a copy of files.db, whether from a previous version, or just making your own backup from time to time. That's your database file. If that file gets corrupted (and they do get corrupted) Ableton will spend dozens of minutes, and depending on the size of your library maybe hours, rebuilding your database.

For this reason I usually leave the previous version's data and just wipe all the others. But it's equally viable to just make a copy of files.db and put it somewhere else on your computer for safe keeping

 

I actually keep forgetting to check those folders, but if I didn't need them I would delete