From what I gather, more than a few people have asked for a permanent fix. The developers of Linux Mint are either ignoring them or consider is so minor of an annoyance that they won’t fix it. I’m using Linux Mint 18. If it’s still an annoyance in future versions, it means they won’t fix it… ever.
In the past, I’ve had to fix a few of my own mistakes and they were anything but easy. This one is easy to do from the command line:
locale-gen --purge --no-archive or sudo locale-gen --purge --no-archive
The directory at /usr/lib/locale/ changed (for me) from:
C.UTF-8 en_AG en_AU.utf8 en_BW.utf8 en_CA.utf8 en_DK.utf8 en_GB.utf8 en_HK.utf8 en_IE.utf8 en_IN en_NG en_NZ.utf8 en_PH.utf8 en_SG.utf8 en_US.utf8 en_ZA.utf8 en_ZM en_ZW.utf8
I’m only concerned about “en_PH.utf8” and “en_US.ut8” because I sometimes switch from one locale to the other (while testing PHP scripts), but it doesn’t hurt to have the rest in there since the files are only 4K each.
Most Linux Mint users use the visual software updater. I prefer not to unless I’m updating the kernel or removing old kernel versions. The software updater seems (to me) to be a bit slower than doing it from the command line. I usually have a terminal session going all the time.
I’ve fixed other minor annoyances in the past but I never thought to share them this way. I’m sorry for that. If I come across any more in the future, I’ll make it a point to share them.