First of all, i would like to say, this so called "perfect" installation of ISPconfig on Centos 5.2 is broken. - One of the things that is firstly wrong is, that yum repositories dont have mysql precompiled postfix at all. (not even dag one) So... this makes whole mailserver broken with this distribution. Other than that, after i fixed problems with recompiling postfix and enabling mysql support, i ran into another problem. the path of maildrop in master.cf of postfix is wrong. - Default installation of maildrop with the centos installation guide is /usr/bin/maildrop, so that should be fixed. You can simply solve it with symbolic link of course. - I have noticed few ajax issues/errors. Sometimes ISPconfig just blocks, and freezes the window. Fortunately it doesn't happen too often. Although, if you are adding a mailbox at that time (like i was), things can get messy. For example, it broke my POP3 and IMAP becouse maildirmake wasn't executed properly and cur, new and tmp directories weren't made properly. Currently biggest issue i currently have is: Feb 16 04:11:38 ibex postfix/pipe: F04DB1A18013: to=<email@example.com>, relay=maildrop, delay=5073, delays=5073/0.27/0/0.02, dsn=4.3.0, status=deferred (temporary failure. Command output: /usr/bin/maildrop: Unable to open mailbox. ) I'm not sure where to start searching for answers to this error, since i was always using Qmail so far on my servers. It's my first time i'm looking at postfix which is supported by ISPconfig which i wanted to try out on the new server i made. I have feeling there must be something with maildrop and mailfilters... not sure. Is there any way i can try "delivering email" manually by su-ing into vmail user and maildroping it manually to the user by issuing it with a command ? That would actually show me where the problem lays. Or maybe how could i log what everything is maildrop doing... in some log file or something... my current maildroprc is: logfile "/var/log/maildrop.log" VERBOSE=5 But for now in maildrop.log i dont have any lines unfortunately.