It doesn’t matter. You know how I know?..because I gave up and bought the new version and used the old  company file and guess what…works since. 
it’s not a computer  issue /update/version. It is Quickbooks loosing some component and then there is nothing to do (at least for an average user)

the best solution ? Buy the new version, it will save you hours- I know it is probably not what you want to hear if you are here.