I then can't do anything in Indesign and get a "Cannot handle the request because a modal dialog or alert is active." message.
I have lots of files that used Type 1 fonts and need to update to Opentype versions of the fonts. I have removed the old font files to make this easier to track but now whenever I open an indesign file with the old fonts, i do not get the missing fonts warning but the software acts as if the warning there.
I have tried finding if the warning was hidden behind another window but it isn't. It popped up correctly once but has not appeared since. I usually have to Force Quit indesign once this happens and that doesn't actually fix anything. I have also restarted my machine and reinstalled Indesign 18.1. Files that I have already updated the fonts in open fine but as soon as I open a file with the old missing fonts it locks up.