SSM - Sheet Rename layout and Rename File Options are disabled

[harilalmn]

Hi All,
I had some previously created drawing files.
I was trying to setup a sheet set, by creating a blank sheet set and then by using the option "Import Layout as Sheet". I imported all the sheets. Then I had to edit the Sheet title and sheet number in each sheet's properties. However, the Rename Options to rename layout tab and the file seems to be disabled for all the sheets in this sheet set. (Please see the attachment)
What could be wrong?

[ScribbleJ]

If the files are opened this will happen. Also if someone else is working within the sheet set then this will lock those options as well.

[harilalmn]

Thankyou for your quick response SribbleJ...
But the files were not opened anywhere in the network and nobody else was working on them...
I confirmed that;
1. Nobody had the files opened (None of the sheets had a lock icon on it)
2. No one else was working on sheet set
3. The properties of the files in the folder was not read only

Now I don't know why this happens...