>The imagefile field did not look corrupted in the way I expected - i.e. containing nonprintable characters. The records for the classes having the wrong icon contained either existing network paths with no file name, or a path + a non-existing bmp file name (the bmp file name was the name of the class).
>Before changing them I tried refreshing the category, but that did not change the imagefile field. I've manually changed the imagefile, and it works ok now, but I'm still a little worried, especially because I suspect some C0...5 I've got in the past were related to the use of toolbox.

Hi Doru,

If you suspect that Toolbox causes those errors, you can close VFP, and rename Toolbox.dbf/fpt. VFP will recreate it and you can add your stuff back to Toolbox.