Nested Cells

Hi,

I see a new phenomenon which never happened to me before.  Cells sometimes lose all nested cells in them. It is puzzling.

I copied a cell library which I wanted to update from the network to a folder in the local drive.  Then I attached the cell library on the local folder and edited some cells. I then copied the cell library back it to the network location. When I load MicroStation I see that some cells have lost all the nested cells.  If I attach the cell library on the local drive it is fine. The size and modified date of both the cell libraries are exactly the same,   Something happens to the cell library when copied to another location.  Does anyone know what the issue is?

Dilip Bhandarkar