I am another longtime satisfied ChronoSync user who was having serious problems with version 4 - hangs and crashes. After going to the product website, I decided to install the add-on product ChronoAgent on my other machine (the one I do not run Chronosync on). This is advertised as allowing a direct (non-AFP) connection between the two machines, with greater speed.

The result for me is a tremendous speed increase in backups, and what seems to be total reliability. Without knowing any of the technical details, I am going to guess that ChronoSync 4 was developed with Chronoagent in mind, and that problems with standard AFP connections went uncorrected as a consequence.

So for ChronoSync 3 users, I strongly recommend installing ChronoAgent (at $10) if you upgrade to version 4. The result will be the familiar ChronoSync 3 reliability plus an enormous increase in file transfer speed. A real, noticeable improvement.

[I should also add that I found the instructions concerning the use of ChronoAgent quite confusing. You install Chronoagent on the machine you are *not* running ChronoSync on; set it up on that machine, following the instructions; then add a new "connection" using the Connections pane of the Chronosync Preferences on the machine *with* ChronoSync (the *other* machine). (You'll need the IP address, port number and other info from your ChronoAgent setup.) Then pick that connection as the location of the folder to be backed up in your ChronoSync document. ]