Internal Server error 500

I receive a 500 error sporadically while calling server workflows to perform SQL queries. It will work consecutively then randomly throw the 500 error. Retrying the Run Workflow activity later on will work at times as well. Updating the database sometimes is successful even though the client workflow states otherwise. The error message from the event viewer on the server states "The process cannot access the file 'C:\ProgramData\Geocortex\Workflow\<subfolder>\<unique ID for the workflow>\Logs|index.csv' because it is being used by another process."