Internal error: Sub-system: FIO, File: /q****/c***/***/***.cpp, Line: 82 Path name is too long -- must be shorter than 260 characters, due to path name length limitations

Description

Due to a problem in Quartus® Prime Software you may see the above error. Quartus does not support long paths when:
 
 1)  Any long path operations are attempted by directly calling the command line executables in Powershell. example : running quartus_*.exe on a project with long paths.
 
 2) Any long path operations by Quartus GUI or by command line are attempted via the normal command shell - example: creating a project with long paths.
 

Resolution

To work around this problem, create the folder in Powershell first before launching Quartus®. 

This problem is scheduled to be fixed in a future version of the Quartus Prime Software.