Fix "Could Not Start QuickBooks" from Multiple QuickBooks Versions in Webgility Desktop
Having two QuickBooks Desktop editions installed on one machine blocks Webgility Desktop from launching the file it is connected to.
Overview
Webgility Desktop can only launch one QuickBooks Desktop at a time. When two editions (for example QuickBooks Enterprise and QuickBooks POS) are installed on the same computer, Webgility can hand the request to the wrong one and show the Could Not Start QuickBooks error (Could Not Start QuickBooks).
When This Applies
Use these steps if the error appears after you installed a new QuickBooks edition on the same computer, or after you upgraded QuickBooks and the old edition is still present.
Why This Happens
Webgility Desktop reads the connected QuickBooks company file from a single integrated application entry. When a second QuickBooks edition is installed, Windows can route the Webgility request to that other edition instead of the one holding the company file, and the launch fails. See Using Webgility Desktop with Multiple QuickBooks Files for how Webgility picks a QuickBooks target.
Steps to Clear the Conflict
Step 1: Open the computer's Control Panel and go to Programs and Features, then confirm which QuickBooks editions are installed.
Step 2: Open the QuickBooks edition that holds the company file you want Webgility to post to, and sign in as the Admin user.
Step 3: Uninstall the QuickBooks edition you do not use. Keep only the edition that holds your Webgility-connected company file.
Step 4: Open Webgility Desktop, go to Connections > Accounting/POS/ERP > Edit Connection, and run Test QuickBooks Connection to confirm the launch now works (see How to Test QuickBooks Connection in Webgility Desktop).
Step 5: If Test Connection still fails, follow Verify QuickBooks Connection & Company File to confirm the correct company file is open and the application permission is granted.
Important Note
Uninstalling a QuickBooks edition does not remove your company files. Your .QBW file stays on disk, so you can keep working in the edition you kept without any data loss.
Key Recommendation
Run only one QuickBooks Desktop edition on the computer that holds your Webgility connection. If your business genuinely needs two editions, install the second edition on a different computer.
Additional Support
If the error returns after you remove the extra edition, contact Webgility Support with the name of the edition you kept and the exact text of the error dialog, so Support can check the integrated application entry on your computer.