Follow below steps to downgrade the EDIUS to earlier build:

Prerequisite (only EDIUS 11 and X):
Ensure if queued or ongoing job is (are) not listed in GV Job Monitor. If exists, cancel or wait for finishing the job. Also, quit EDIUS, Mync (or both) if running.

Procedure:

1) Sign into the OS with administrator privileges

2) From Apps & features, uninstall below programs

3) Open C:\ProgramData\Grass Valley folder

4) Rename EDIUS Hub to EDIUS Hu_ (EDIUS X only)

5) Restart the OS

6) Run the earlier build installer