ASM-00001: Could not open device

While doing ASM installation on Windows System , we faced the following issues.

OS version : Windows 2008 R2

Grid version: 11.2.0.3

When  I was trying to run the "asmtoolg" command to stamp the ASM disks, we were getting the following error. Tried many things , including dropping and recreating the LUNS  , still we could not resolve it.

Solution :

Solution  of the problem is very simple. when you are invoking the asmtoolg.exe or setup.exe , just right click and "Run as Administrator". Thats it , issue resolved


Cause:
On windows 7 and Windows Server 2008 , is spite the user having Administrator Priviedges,
By default all the programs are run as " Non Admin" privilege and we need specifically "run as" administrator if needed.