How to change Grasshopper autosave file location

Hello. My C drive recently is a bit cramped of space and unfortunately there is very little of it that I can get rid of. Therefore I was wondering if there is a way to change the Grasshopper autosave file location from C drive to D drive in settings?

I’m just a regular GH user with no knowledge of the software’s internal code, but I expect the name of the autosave directory is hard coded into the program (along with the other directories in the “Special Folder” list.) But the good news is Windows provides a way to deal with situations like this.

The technique uses something called a Junction Link. There is an old program that still runs fine called Junction Link Magic that lets you create and remove Junction Links. A Junction Link is like a shortcut, except it works at the internal Windows level. (Junction Links were not meant for normal people to use - but oh well.)

Junction Link Magic lets you create a link/shortcut on the C: drive that points to a same named file (or directory for that matter) that is physically on some other disk. When any Windows program (or Windows itself) tries to access that file or directory all it’s read/write actions happen at the other location, because the Junction Link redirects them there. In other words, it works like magic.

I’ve done this for quite a while with a few temporary type files I want off my C: drive. You have to be careful what you do this with because some Windows files & directories have to stay physically on the C: drive. If you try to move such a file or directory off the boot drive your PC will crash.

Making a Junction Link for the autosave file is easy:

  1. Copy all the files in the autosave directory to a different drive and put them in a new directory which you can name the same as the GH autosave directory or anything else you want to call it.
  2. Delete all the files from the real GH autosave director on your C: drive.
  3. Use Junction Links Magic to connect the empty C: drive directory to the new one you created in step 1.

That’s it - when you reboot GH will think nothing has changed, but Windows will redirect all I/O to the new location. If you use a file manager to look at the contents of the recovery file on the C: drive it will show them all, but they really aren’t there - they are in the new location you created in step 1.

Thank you so much Birk for your detailed instructions! I will this out. Hope you have a nice day!