Resharper Cache size uses huge amount of disk space

I noticed that my development machine running windows server suddenly ran out of space. I ran WINDIRSTAT and see that Resharper cache is using a LOT of space..

It's a normal web project including 3 class projects as well.. The other projects on the server uses about 10 MB and this project 11 GB.... What can cause this?

I don't really know what's gone wrong here - 11GB is rather excessive! I'd suggest resetting the cache (just close the solution and delete the redacted folder, or click the "Clear caches" button in the ReSharper → Options → General options page), and reloading the solution. The cache should be considerably smaller. It would probably be worth updating to the latest version of ReSharper (9.1.1 is the latest released, 9.2 is in EAP builds). If the cache is still this big, contact support, either by emailing support at jetbrains dot com, or by raising an issue directly at https://youtrack.jetbrains.com

EDIT (23/02/2018): Removed the section on integration with Windows disk cleanup. Sadly, this isn't a completed or released feature.