Photoshop fonts problem

[cool11]

I have a problem with photoshop cs6. I just updated to 6.1 too, but even now the problem remains.
The problem appears when I try to open a third-party psd file which contains a font that my mac does not have.

At first, photoshop displays a message that my machine does not have the font and if I want to use a substitute. I click yes and then it opens the file.
After this momment, the problem appears.
Photoshop seems to hung, the standby spinning ball appears all the time, photoshop seems no responsive, and I cannot do anything than force quitting.

I really do not know why photoshop handles the situation like that. I cannot work when I want to use these files with missing fonts.
I don't really want to find original fonts, I just want to make my work ignoring what the original fonts were.

Is there a solution? Can you imagine where the problem is?