Hi There,
I've been recently experiencing problems with connecting more than one firewire drives directly to the existing computer ports.
I use MacPro tower, leopard 10.5.5

When I have one drive already connected and try to add another external drive it either doesn't pop up, or the one that is already connected goes offline.

I first noticed it when I was trying to use simultaneously either 2 800 firewire ports (one on the back, another on the front) or 2 400 ports (i never cross connect 400 and 800).

To resolve the issue I bough a 400 firewire hub, and decided to start connecting the drives only this way. Unfortunately, the problem persists, i.e. I work normally with two drives (connected right after I start the computer), and if I later add the third, the system goes crazy.

I have similar conflict using the eSATA ports. I use one eSATA slot only for a 5tb drive that is permanently on and I can never connect anything else to the remaining ports, because the earlier connected drive goes suddenly offline.

What could be a possible reason for that? Could that be a faulty e-sata card? (it is sonnet tempo SATA E4P, installed to the only PCI express slot so no mistakes here possible). i noticed other strange issues after installing this card (and i had to take out one of my 3 graphic cards to do this): FCP often refuses to render simple graphic effects saying that it is not possible with current graphic card (and I have now two of them, both factory installed cards ATI Radeon HD 2600 XT)

Thanks in advance for your advice

Almost sounds like a motherboard problem. I would get it looked at. If you have Applecare, you should have no problem getting service on your FW ports.

The eSATA problem though could be an issue with the particular card you have, or the drive. It's harder to tell what's wrong.

Andy

Thank you.