Part file descriptions disappear from windows explorer. Why?

I have a variety of fasteners.  The file name for each fastener is an assigned a part number (for example:M0-0001-15-4).  The description is the descripton of that fastener(for example:SCREW 1/4-20 X .375 HX CS SS).

Whenever I open any fastener part, in an assembly or by itself, the description disappears from windows explorer (also from the "insert part" browser box).

As soon as i close that part in solidworks, the file descriptions will reappear.

Anybody know why this is happening?

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