Access to "c:\....\MFC1F8.tmp" was denied

Hello,

I meet a problem with keil, when I'm trying to save an header file sometimes I get error: "Access to c:\....\MFC1F8.tmp was denied" followed by error: "Could not write file - c:\...\myfile.h"

Once I get this error I need to: Save the header file to another place, Close keil, Rename header file to the correct name, Re-open Keil

The reproduce rate is approximativeley 10% and only happen on header files (Everything is properly working for .c files)

I disabled my antivirus and I'm sure to have write access to my source folder.

Does anyone already met this issue ?

FYI, my keil version is: 2.21a and I'm able to reproduce this error with 5.20 too.

Any help would be appreciated.

Thank you,
Regards,
Thierry.