Windows 11 CopyToCache returns COM-Error 0x80246fff

Question

We already had the problem with cumulative patch KB5048667 from January: CopyToCache returns “COM-Error: 0x80246fff” - according to the documentation:

WU_E_DM_UNEXPECTED There was a download manager error that is not covered by another WU_E_DM_* error code.

It is the case that each individual download file belonging to the patch causes this error, so that it cannot be linked to a single file.

Seen on a Windows 11 24H2 client, also occurs directly during the first update check, so that no update cache etc. can be the source of the error.

Unfortunately, the same problem exists in February with the cumulative patch KB5051987 - which replaces the above-mentioned patch. So the problem is still not solved.

Data from the Windows 11 client on which the error is reproducible: Windows 11 24H2 - Build 26100.2605

Installed hotfixes (get-hotfix): KB5042098, KB5048779, KB5050575, KB5049685

KB5048667 is also installed, we have done this manually via the separately downloaded msu file - but this is not a permanent solution for us for all upcoming patches.

Can we hope that the problem has now been solved in February and that CopyToCache will work again with the next update in March at the latest?

We would be pleased to receive feedback on how to solve the problem. In my next comment is an example in C++ with which this can be reproduced. It is a simple example, the patchscan.cab file is expected under c:\temp and the downloads are stored under c:\temp\WSUS - adjust the directory if necessary.