ZetaTSB

Ok! so i am having an issue that just recently came up the modpack was working just fine no issues at all up until about a day ago it now says delete or install so when i click install thats all it does it runs the process but does not actually do anything just the same two options and im at a loss here ive tried redownloading the launcher went through the files all of it and cant seem to fix it any help would greatly be appreciated cause i dont even get an error message it just repeats that over and over