Serious! Windows 2012 RDS cannot start / refresh anymore!

Question

I go a problem which seems serious, please help to comment if any idea..
I have a Windows 2012 server with RDS / Hyper-V installed and configured properly; I created 4 virtual desktop collections (Win7/Win8) and they were all running well; then I tried to create unmanaged virtual desktop pool with Win7/Win8 -- somehow it
did not work and reported error message advising that the creation had failed; I then tried to create unmanaged pool with W2K8R2 and it worked -- however, RDS cannot refresh in server manager anymore, and after I restarted the server, the RDS cannot view cannot
display anymore in server manager e.g. the collections are not shown and it keeps refreshing but no output.
I tried to access RD web access and it still works -- however I can see the unmanaged pool of Win7/Win8 there which should not exist as they failed; I clicked on them and they were just empty;
I can see an error message in RDS Servers/Events saying there is a collection "NULL" so the DB visit failed;
It looks to me like Windows RDS failed to create the 2 unmanaged pools but they did get created in DB so the conflict is now blocking the RDS to continue; problem is now there seems no tool/option to fix it?
Any advice please?
Thanks,
Leon Li

Answer 1

So it seems I discovered this bug almost 1 year later (using Windows Server 2012 RTM + RDS/Hyper-V for VDI).
Leon Li guided me to the cause and solution (thanks!) but you must be very careful editing the WID (windows internal database).
In my case, problems started after attempting to create a new unmanaged personal desktop pool in an already working environment which hosted a single virtual desktop pool. I hesitated when creating the new pool and entered the wizard GUI a couple of
times before attempting creation. As described by Leon Li, it seem an internal counter is not reset in the GUI when creating new pools, causing consecutive attempts to fail (actually the pools are created in the background, just not completely). You can see
this by viewing the "partial" pools via rds web.
My solution was to edit the rds.pool table and remove the pools which had failed being created (it was quite simple to identify them by name, but actually the tell tale sign is a NULL value in the "ResourcePluginName" column).
After deleting the problematic rows, my server manager became responsive once again and I am able to manage existing collections once more.
To clarify, you must install SQL management studio on the connection broker and use it to connect to:
\\.\pipe\MICROSOFT##WID\tsql\query. You must "run as administrator". In there you can find the database RDCms where the editing must
be performed on rds.pool table.