Error: There was a failure to call cluster code from a provider. Exception message: Generic failure . Status code: 5015. SQL 2012 SP1

Hi,

Please help. I was trying to remove a SQL 2012 SP1 two node clustered instance using setup (Mantenance -> Remove Node)

I started by doing this on passive node (and was successful) but when I ran setup on active node just before finishing successfully I got this error:

TITLE: Microsoft SQL Server 2012 Service Pack 1 Setup
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The following error has occurred:

The resource 'BCK_SG1DB' could not be moved from cluster group 'SQL Server (SG1DB)' to cluster group 'Available Storage'. 
Error: There was a failure to call cluster code from a provider. Exception message: Generic failure . Status code: 5015.
Description: The operation failed because either the specified cluster node is not the owner of the resource, or the node
is not a possible owner of the resource.
.

For help, click: http://go.microsoft.com/fwlink?LinkID=20476&ProdName=Microsoft%20SQL%20Server&EvtSrc=setup.rll&EvtID=50000&ProdVer=11.0.3000.0&EvtType=0xE8049925%25400x42B4DED7

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BUTTONS:

OK
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I noticed that SG1DB instance was removed on both nodes but on Failover Cluster Manager -> Services and Applications the SQL server instance for SG1DB is still there. So I tried to delete it but got the error:

Failed to delete SQL Server SG1DB. An error was encountered while deleting the cluster service or
application SQL Server SG1DB. Could not move the resource to available storage. An error occured
while moving the resource BCK_SG1DB to the clustered service or application Available Storage
...

Any ideas why it failed or how could I delete the SQL server instance from Clauster?

Thx