After installing FontReserve fresh off a new packaged CD, the classic Xtension for Quark 3-5 actually broke Quark, prohibiting it from opening under Classic mode. It would launch and then immediately shut down until you removed the FontReserve Xtension from the Xtensions folder. I checked and found the FontReserve 3.1.4 update and decided to give that a shot. Ironically, this "update" actually installs version 3.1.2 of the Quark 3-5 Xtension instead - so they must know something was wrong with the 3.1.3 version. Now Quark launches and behaves as expected. So go back to the 3.1.2 version if you are having problems.