If you're using a Parallels virtual machine and share your Mac folders (Desktop, Documents, Downloads) with the Windows environment, Revit may have difficulties with saving your model files to these folders.
The problem is caused by Revit being confused about resolving the file paths for these shared folders. Parallels is doing some special things to map these Mac folders to equivalent folder in your Windows environment and make them available there, but Revit has trouble accessing these special shared folders.
The solution is to change the configuration of your virtual machine turn off the folder sharing for folders that you'll be accessing from the Revit application.
- Shut down your Parallels virtual machine.
- Select the virtual machine in the Parallels Control Center window, then choose Action > Configure to open the configuration settings.
- On the Options tab, select the Sharing settings.
- Switch to the Share Mac pane.
- Turn off the Share Mac user folder with Windows checkbox.
- If you'd like to have some Mac folders appear in the Window environment (ones that you won't being saving Revit files to), click the Custom Folders... button to select the folders to share
- In the Share Folders section, you may need to enable sharing of "Home folder only"
- Restart your virtual machine.
- On the Windows desktop, you should see a folder called "Mac Files" with a "Home" folder nested inside. You can access any Mac files saved to your Mac environment through this folder structure