Doesn't work on High Sierra

[ZhiliangWu]

on 10.13.6, tried to copy the file, either in ~/Library/Quicklook and /Library/Quicklook. Doesn't seem to work with quicklook. (qlmanage -r given and even restarted the Mac)

[Watson1978]

Thank you for your report and sorry late reply.
Seems that I need more information to solve your issue about your machine specs, etc.

If you have been used other QuickLook plugin, could you remove them at first?

[christopheranderton]

Confirmed working on both macOS 10.13.x High Sierra and macOS 10.14.x Mojave. Like @Watson1978 wrote, try to remove any .qlgenerator plug-ins temporarily in:

/Library/QuickLook/  (except iWork.qlgenerator and iBooksAuthor.qlgenerator, as they are from Apple) and if any in:
~/Library/QuickLook/

And then restart (shouldn't be neccessary, but there is a bug in the macOS QuickLook Server that sometimes requires a restart). Then do qlmanage -r or qlmanage -r cache && qlmanage -r . If it works, try to add the removed .qlgenerator plug-ins one after one (and do a qlmanage -r everytime).

If you have MultiMarkdown QuickLook.qlgenerator or QLMarkdown.qlgenerator installed, they are most likely the culprits.

You can also run qlmanage -m plugins in the Terminal, which lists active qlplugins. Note that most plug-ins are listed inside app bundles and not in ~/Library/QuickLook/ or /Library/QuickLook/ However the qlplugins installed by the user should take precedence.