The only working fix in this state
Clone the form using “Copy” (NOT recreate)
This preserves:
All questions
All settings
Branching logic
Theme
…and forces Forms to provision a new response backend.
Step-by-step
- Go to forms.microsoft.com
- Locate the affected form
- Click the ⋯ (three dots) on the form card (not inside the form)
- Choose Copy
This creates Form (1) or similar.
Then:
- Open the copied form
- Submit one test response
- Go to Responses
In almost all cases, you will now see:
Download a copy in Excel working
Often Open in Excel Desktop / Online restored
The export engine is newly created for the copy.
What about the old responses?
Because your original form cannot export at all, there is no supported way to recover those responses into Excel.
However, you can still:
Use Check individual results
Manually copy/paste response values if absolutely necessary
Keep the original form for audit/reference
Use the copied form going forward
Microsoft does not offer backend recovery for corrupted Forms exports unless you open a tenant support ticket.