Connecting to QuickBooks Desktop
Fix QuickBooks Desktop connection error 80040154 (class not registered)
In short
80040154 is Windows' "class not registered" error: the app asked for QuickBooks' connection component and Windows couldn't find it in the form the app needs. With OK Book Sync, it almost always means the 64-bit app is on a PC with QuickBooks Desktop 2021 or older, which is 32-bit. Install the 32-bit (x86) version of the app instead. Your settings are kept.
Check which QuickBooks you have
Open QuickBooks Desktop and press F2. The Product Information window shows the edition and year, like QuickBooks Desktop Pro 2021. QuickBooks Desktop 2022 and newer are 64-bit. 2021 and older are 32-bit. QuickBooks Enterprise shows a version number instead: 21.0 or lower is 32-bit, 22.0 or higher is 64-bit.
Fix it
- Close the app: open Settings and choose Quit.
- Uninstall it from Windows Settings, then Apps. It's listed as Toast to QuickBooks. Your settings and history stay in your Windows AppData folder.
- Download the 32-bit installer: okbooksync.com/download/windows-32. Signed in, your account page has it too, with your license key built in.
- Run it, open the app, and connect QuickBooks again.
Still seeing it?
- QuickBooks has to be on this PC. The app talks to QuickBooks on the same PC, so it can't reach a copy that's only installed on a server or another computer.
- Just installed or updated QuickBooks? Open it once, open your company file, then connect from the app.
- Still stuck? Email [email protected] with your QuickBooks version and the full error, and we'll sort it out with you.
Connecting for the first time? Here's how to answer QuickBooks' permission prompt.