Thanks for joining the thread, @Janey8228. I'm pleased to help you with the concerns you have about your QuickBooks Desktop (QBDT) for Mac company file.

To go back to a previous backup of your company file from when you were using QBDT for Mac, you can do so by restoring it. Here's how:

1. Navigate to the QuickBooks menu and select Settings.
2. Choose Backup and then Reveal Backup Folder.
3. Double-click the folder where you save your backup files.
4. Click Date Modified to sort by date and find your latest backup.
5. Once you've located your backup file, double-click it to open a new window displaying a copy of your company file. If you've attached documents, you'll see a folder called Attachments Library.
6. Drag the copy of your company file to the folder where you store your QB company. If you also see the Attachments Library folder, drag it to the same area.
7. Open QB for Mac and select Browse.
8. Go to the folder where you saved the copy of the company file, select the file, and click Open.
9. A prompt will notify you that you're opening a backup file. Choose Continue.
10. Input a name for the company file, hit Save, and then OK.

For more detailed information on this process, visit this article: Restore your backup company file for QuickBooks Desktop for Mac.

Additionally, there isn't a direct way to undo an update or migration. However, you can move from QuickBooks Online (QBO) to QBDT for Mac. To do this, you'll first need to export your files from QBO to QBDT for Windows, and then convert them to Mac.

To know more about how your books transfer from QBO to QBDT, check out this article: Learn how features and data move from QBO to QBDT.

Go back to this thread if you have any other concerns besides your QBDT for Mac company file. Our team is always eager to help you out. Take care and have a good one!