One of the most common reasons for getting QuickBooks error 6073 is having improper hosting configuration. For quick troubleshooting, follow the instructions given below:
Open QuickBooks on the computer where the company file is already opened.
Now click the File tab and select Utilities drop-down.
Click the Host Multi-User Access option.
Once the QuickBooks starts running in Multi-User mode, try to access the company file once again.
In case if QuickBooks error 6073 reappears while opening the company file, you must contact a certified QuickBooks Desktop expert for help. You can reach our team of certified QuickBooks Desktop experts at 1-855-856-0042.