MarkEdit: QuickLook Extension can be broken by iA Writer

@cyanzhong I’m also experiencing the issue described here.

I had iA Writer Classic installed (via Rosetta) when I installed Markedit alongside it by downloading it from GitHub.

• I’ve deleted iA Writer Classic and cleaned up all of the applications files and extensions it left behind.
• I’ve restarted my machine and relaunched Finder multiple times.
• The QuickLook extension appears registered in System Preferences, and looks to be running in Activity Monitor.
• I’ve also checked mdls and it recognises the file as kMDItemContentType = app.markedit.md.
• I have Sublime Text installed (not sure if this is relevant, but I saw it mentioned).

Previews looks like this:

I tried a .mdown file extension and got this error:

I noticed there’s a crash report in Console:

crashreport.txt

The preview extension crashing seems to also cause System Preferences to load and then crash instantly.

Indeed from what I can see they don’t register any extensions for it or anything like that. Regardless, with the new title it should be searchable for anyone that has trouble.

Thank you for confirming! That’s a very interesting finding.

Yes, I can find MarkEdit in System Settings > Privacy & Security > Extensions > Quick Look. Toggling it does nothing, including after I relaunch finder. PreviewExtension.appex is present as expected, both in github release version and homebrew version.

However, there is no MarkEdit processes at all, unless MarkEdit (the app itself) is running. Even then, there is no process mentioning Finder. It doesn’t show up even with the app store version.

I tested a few other extensions, and the qlmarkdown extension seems to work as expected, so it’s not a general “quicklook doesn’t use any extensions” problem. There does seem to be something funny to do with markdown in particular though, since I also checked the bear quicklook extension and ttscoff’s mmd-quicklook (a generator), neither of which had any noticeable effect (the latter, being a generator, didn’t do anything even when invoked with qlmanage).

I honestly have no clue as to how to debug this, since it does seem like some plugins can work on the same files that fail otherwise.