Two questions: Duplicate files & how to move transactions

• The /Library/Application Support/Quicken/Documents folder is the default location where Quicken will create new data files if you don't tell it to put them somewhere else. So if you were creating new documents it's likely at some point that one would get created there. If you don't need it you can delete it.

As for putting your data file in the Documents folder, the only possible downside to that is if you have the Documents folder set to sync to iCloud. You don't want to keep your data file in a location that's syncing to iCloud, it can cause the file to get corrupted. If you're not sure whether this syncing is enabled, go to System Settings, click on your Apple Account at the top of the sidebar on the left, then click on the Drive pane. If the "Desktop and Documents Folders" option is enabled then the Documents folder is being synced to iCloud and you will want to put your Quicken data file somewhere else.

As for exporting your Fidelity account & importing to your Business file, probably not. There's no way I know of to export & import an investing account; the only option for doing this is via a CSV file and that only supports cash transactions. If the account in question is a CMA that only ever held money in the core position & never had any investing transactions then you could make this work, but it would take a fair amount of manual labor on your part since the CSV file exported from Quicken cannot be directly imported again, it has to be reformatted.

OK, I did think of a way to move an investing account over to your business file but it takes a fair amount of work on your part. First make a backup of both data files just in case something goes wrong. Then make a copy of the Quicken data file with the account you want to move & open the copy (make sure you're not working in your original file!). Now delete every account except the one you want to move, including any closed or hidden accounts. There's no quick way to do this, you just have to go through the accounts in the sidebar and delete them one by one. Then delete any other extraneous data you don't want moved over to the business file - for starters any categories, tags, or payees that are now unused. Also delete any renaming rules or QuickFill rules that you don't want moved.

Once all that is done you can export the file. Go to the File > Export menu and choose the "Quicken Transfer File (QXF)" option. Save that file wherever you like. Then open the data file you want to move the account into and from the File > Import menu select "Quicken Windows File (QDF, QXF)". Choose the file you just exported. You might want to make a copy of the business file you're importing to and import into the copy just in case you don't like the results & need to make adjustments. Once you're satisfied with the result you can import into the original business file.

Note that any transfers into or out of that account that went to other accounts within your Quicken file will no longer be connected to those accounts.