After facing QuickBooks error 15106 myself, I looked around and wanted a quick solution to it, and here are the steps that fixed QuickBooks error 15106 for me.
1. Open QuickBooks Desktop.
2. Click on Help and choose Update QuickBooks.
3. Select mark All under the Options tab.
4. Click on Save and move to the Update Now tab.
5. Checkmark Reset Update now checkbox before you hit on Get Updates.
I hope the steps I mentioned solved the issue for you and if you still come across QuickBooks error 15106, consider contacting the QuickBooks Expert team.
