I just found this, and it almost falls within the realm of "too good to be true". Does anyone here use UPX to compress their exe's? Are there any side effects or compatibility issues? I've only got one test machine, and it works fine for me (it compressed a 1.3MB exe to <700K.) .. there's got to be a catch to this miracle product right?

http://upx.sourceforge.net

Well there's no miracle in compression. All it does is changes the size of the file on disk, it still has to be decompressed when loaded into memory. Zipping the EXE should give you the same result in theory.

I love UPX. From what I've seen, UPX does a better job of compressing executables than Zip alone. It's worth testing on your own files to be sure. Plus it reduces the amount of disk space your client's hard drive just to be nice. :) I don't notice any delay during decompression. Also note UPX works on most DLLs too.

Here's some numbers for one test I did:

RegularFile.exe 381k
UpxFile.exe 112k
RegularFile.zip 145k
UpxFile.zip 110k

Zipping the UPX results in marginal savings, but at least it doesn't get any bigger. :D

Yeah, upx is great. However I use a commercial software protection system to compress my main executable. On all other runtime library I use upx. Upx was designed by a hungarian guy which made my decision easier. :)

A very simliar question was recently asked on the ASP member forums ...

The consensus was that while UPX might have/maybe triggered false virus alerts from earlier version of some anti-virus software, some authors have been using it for years with nary a problem.

David