Some Windows 10 users may be blocked from upgrading to Windows 11 unless they import IE11 data into Microsoft Edge. The data is not properly migrating over from the previous version of Windows. The issue only seems to affect systems in which Internet Explorer was made the default browser. A solution for this should arrive in a future Edge update.
Issue Details
After upgrading to Windows 11, saved information and data from Internet Explorer 11 (IE11) might not be accessible if you did not accept to import it into Microsoft Edge before the upgrade. Note: If you have accepted to import your IE11 information and data into Microsoft Edge in Windows 10 before upgrading to Windows 11, your device should not be affected by this issue.
To safeguard your upgrade experience, we have applied a compatibility hold on devices affected by this issue to prevent them from installing or being offered Windows 11. Affected devices are those in which IE11 is the primary browser used or IE11 is set as the default browser. If your organization is using Update Compliance, the safeguard ID is 37820326.
Next steps: We are working on a resolution and will provide an update in an upcoming release of Microsoft Edge. The issue should be resolved for devices that have not yet upgraded and devices that have already upgraded to Windows 11 without accepting to import IE11 data into Edge.
Source: Microsoft (via Bleeping Computer)