I am using Inkscape .48 on a machine running Vista Business. I recently purchased and installed Trajan Pro-Regular, open-type. I restarted Inkscape, used the font, and it appeared that everything was working well. The next time I opened the file, the dropdown list said "font not found on system". I did a bunch of research on this website and the larger internet, but found no help. I tried reinstalling the font, which makes the font work properly, but only until the next time the computer is restarted. After a restart, the font again appears with the "font not found on system" message. Many thanks for your suggestions.

Update: The problem turned out to be unrelated to Inkscape, but I thought that the resolution may help others, so here it is:

The folder containing the font was encrypted when I downloaded it. I removed the encryption [from the folder properties window], reinstalled the font, rebooted the computer, and it was finally usable!

Hi heidikswenson,
Thanks for sharing. I've had a similar problem, so will look for encrypted files.....although I wonder why you could install without decrtypting first??