Users may encounter error messages such as “Disk full while accessing” or “There is not enough space on drive C” when attempting to save or sync a model in Revit. These messages indicate that there is insufficient space on the disc drive to perform the necessary actions in Autodesk Revit.
To resolve this issue, users must free up space on their computers by deleting unnecessary files. Some Revit-related files can be safely deleted periodically to free up space. These include journal, temp, CollaborationCache, and PacCache files.
To delete these files, users can navigate to the corresponding folders on their computer and delete the files located there. However, it is important to note that CollaborationCache and PacCache files are related to Revit cloud models’ local cache. As such, after deleting these files, Revit cloud models may take longer to open the first time, and users should be aware that they are deleting their locally cached copy, which may be needed for other purposes.
Additionally, users may consider redefining the Windows user variable TMP to point to a folder on another drive with more space, if available.
How to fix “Disk full while accessing” or “There is not enough space on drive C:” errors
 In the following we will see how to solve this problem technically:
Issue:
The subsequent messages appear when saving or synchronizing a model in Revit.
Revit
The access failed due to insufficient disk space.
C:\Users\username\AppData\Local\Autodesk\Autodesk Revit\<filename>.rvt
Revit
The drive C: does not have adequate space to generate the necessary temporary files for Revit. To resolve this issue, free up space on the drive or redefine the Windows user variable TMP to a folder on another drive with more available space.
Causes:
Insufficient disk space is preventing the use of Revit for working with models.
Solution:
To resolve the problem, consult the guidelines below for freeing up storage space:
Please be aware that creating additional space on your computer is beyond the scope of assistance provided by Autodesk technical support.
You may choose to delete certain Revit-related files periodically. Here are the details:
– Journal files: The file path is located at C:%username%\AppData\Local\Autodesk\Revit\Autodesk Revit <release>.
– Temp files: With all Autodesk software closed, navigate to the temp folder (type %TEMP% in Windows File Explorer and press Enter), then delete as many files as possible.
– CollaborationCache files: Remove the files in the CollaborationCache folder at C:\Users\username\AppData\Local\Autodesk\Revit\Autodesk Revit 20xx\CollaborationCache.
– PacCache files: Delete the files located in the PacCache folder at C:\Users\username\AppData\Local\Autodesk\Revit\PacCache. Note that the Logs folder cannot be deleted.
Note: Please keep in mind that removing the CollaborationCache and PacCache files impacts the local cache of Revit cloud models. As a result, the first time you open Revit cloud models after the cache is rebuilt, it may take longer. Additionally, please be aware that this action will erase your locally cached copy, so it will no longer be available if it’s required for any other purposes.
Source: Autodesk Support
