The program is not responding.
Operating multiple characters at the same time, the program did not respond.
The program didn’t respond when opening a large font file.
There is still a lot of capacity in computer memory chips.
The CPU is not 100%
The program is stuck for a long time.
Depends on the complexity of the font and if generating friendly glyph names is enabled. It can take a long time, several minutes, maybe even an hour.