Re: Running multiple versions of Quickbooks
As of the moment, you're unable to pull up and access your QuickBooks product with different versions at the same time.
One of the reasons is the error you have received when accessing your QuickBooks Premier 2017 and the 2018 versions.
As always, you can visit our Help Articles page for QuickBooks Desktop if in case you need some tips and related articles for future use.
If there's anything else that I can help you with, please let me know in the comment section down below. I'll be always around ready to help.