Errors Caused by Reinstalling an Operating System
From Autodesk Stand-Alone Licensing
Errors Caused by Changes to License Files
License Errors
Errors Caused by Changing the System Date and Time
If you reinstall your operating system on the computer where your Autodesk license resides, the license might fail. You won't be able to use your product.
To resolve a license error in this case, you must reactivate your product. See Register and Activate an Autodesk Product.
To prevent a license error when you reinstall an operating system