do you have any antivirus type software on the mac?

Make sure you disable airpot on the mac before connecting the ethernet for RB

what if you plug a cdj right into the mac, biassing the switch, does it work properly then? Could be switch related

make sure you ethernet in preferences is set to DHCP

Thanks for your reply - unfortunately the problem remains.

No antivirus type software on my mac (and all other programs closed too), Airport disabled and ethernet is using DHCP.

Direct link from CDJ to the laptop has the same issue.

hhmmm........ any other ideas?

Has it just started to happen or has it been like that since you installed RB?

Also is there any other machine you can test it with to eliminate if it is anything on the macs side?

Just an fyi, It is definitely not the amount of files, I have over 22,000 and RB is pretty much instant when I plug in

Also try different cat5 cables

its a totally new setup with the CDJ900's and rekordbox, so yeah has been happening since the 'begining' so to speak, tried both cables that came with the CDJ's and another cable and no difference. 

ive got a windows laptop ill be able to test it on tomorrow, but i can't rely on that to use all the time.

im leaning towards a rekordbox re-install. can't do any harm?

Nope can't do any harm try it and see what happens, backup your database first though ;-) I'm leaning towards a communications problem.. Do you have your mac connected to any other network for internet ie wifi?

think your on the right track. tried a re-install and i can't get the CDJ's to work at all now can even see rekordbox on them.

I get connection pop ups such as 'do you want to allow rekordbox to accept incoming connections' however they pop up and disappear so quickly i can't click 'allow'. i finally managed to click allow on a few of them but my CDJ's still can't see rekordbox at all. 

seems the re-install has done some harm lol

I'm not a Mac person so I can't really help but it really does sound the same as the built in firewall exceptions in windows!  I'm sure Pulse will tell u when he reads it

ok I've fixed it!!! Thanks for all your help and ideas. heres what finally did it:

I tried messing with Mac OSX firewall (on and off) and nothing was working. so i was went to the application folder where rekordbox is and within in that is another two programs called 'PSvLinkSysMgr' and 'PSvNFSd'. just out of curiosity i tried to run these and i got a prompt to allow incoming connections. i clicked allow and then my CDJ's popper up in Rekordbox (in the link at the bottom). 5 seconds later and i can see the rekordbox library on my laptop and browse tracks. YAY.

Thanks again for everyones help

Nice one, glad u got it resolved, now you can have fun :-)