Yesterday we covered a report from a reader who has having trouble combining .mov segments into a single file; after disabling Unsanity's Application Enhancer, the problem went away.
We should point out that this doesn't necessarily implicate Application Enhancer itself as the source of the problem. Disabling Application Enhancer also disables any installed Application Enhancer modules; if one of those modules is the actual cause of the conflict, disabling Application Enhancer may appear to fix the problem because it also disables the problematic module. (This is similar to Mac OS 9's Shared Library Manager files, which supported a number of shared libraries -- disabling the SLM files would "fix" any problem caused by a shared library.)
In other words, disabling Application Enhancer itself is most likely overkill, especially if you want to use other Application Enhancer modules. Two alternative solutions are to disable individual modules one at a time until you find the culprit, and/or to use the APE Manager preference pane to exclude those applications that appear to conflict with Application Enhancer modules.
The reader who reported the problem yesterday mentioned that Application Enhancer showed up in the QuickTime crash log, implying that it was the cause of the problem. One of the Unsanity developers noted that APE will appear in every crash log, simply because it spawns a "listening" thread in every application; however, this thread doesn't actually affect the application at all; it simply listens for particular system messages. In fact, the developer stated, "I can guarantee you it is not caused by APE."