Assembly Error on Workflow Instances

Topic

All workflow instances are hitting the same error message below:

Could not load file or assembly 'CSWinWF-{GUID}, Version=0.0.00, Culture=neutral, PublickeyToken=null' or one of its dependencies.
The module was expected to contain an assembly manifest.

Instructions 

1. Restart the K2 Server Service then
2. Retry the workflow instance in error from K2 Management