QuickLook Does Not Open .txt Files Anymore
In case your QuickLook function on Mac OS X 10.11 or up stops previewing plain
text files — and only plain text files —, don’t depair. Just remove the
QLColorCode generator from ~/Library/QuickLook and exchange it for an
updated one that actually works. Afterwards run qlmanage -r to reload
all generators.
I found out that the QLColorCode generator hijacks public.plain-text by
running qlmanage -m | grep text. Since code highlighting wasn’t working for
quite some time I figured this might be the reason text preview also fails.
Which turned out to be true.
All other solutions I found on the web did not work.