If you have SSRS files filling your temp drive, look for the RSTempFiles.
Default folder:
C:\Program Files\Microsoft SQL Server\MSRS11.MSSQLSERVER\Reporting Services\RSTempFiles
You can move this folder to a different drive by copying the RSTempFiles folder to the target drive (for this example "R:\RSTempFiles").
Make sure that the SSRS service account alias has full permissions on the folder
Default local machine service account alias:
[NT SERVICE\ReportServer]
Locate the rsreportserver.config file
Default folder:
C:\Program Files\Microsoft SQL Server\MSRS11.MSSQLSERVER\Reporting Services\ReportServer
In this file Located the <Service> tag and add entry for FileShareStorageLocation with new path:
<Service>
<FileShareStorageLocation>
<Path>R:\RSTempFiles</Path>
</FileShareStorageLocation>
...
</Service>
After saving the file restart the SSRS instance. It should start using the new location.
For more info about the files stored in this folder:
https://blogs.msdn.microsoft.com/jgalla/2008/06/30/all-those-temporary-files-rstempfiles/
