arduino uno hangs host computer at startup

hi
i’m using an arduino uno (R3) connected through usb to a mac running 10.6.8.
whenever i start or restart the host computer with the arduino connected, the mac freezes
(after the boot sound only white screen, not even the apple appearing).
i can see the uno board getting power from the usb port and starting it’s programm (simply led on pin 13 blinking).
the mac can’t recover even if i unplug the usb cable. only hard reset possible.

tested on 3 different computers with two different uno boards.
duemilanove works fine, though.

this seems to be a very fundamental problem, but i can’t find anything in the forums about it.

where am i going wrong here?
thanks,
p

Here, maybe:

https://discussions.apple.com/thread/2138237?start=0&tstart=0

I also saw a suggestion to make sure your startup disk is set to your hard disk.

palomino: this seems to be a very fundamental problem, but i can't find anything in the forums about it.

I don't have an R3, but my Uno doesn't give my Mac any startup issues.

Same problem here. OSX 10.6 and it freezes with a UNOr3 AND a brand new arduino mega 2560. Any hint on how to solve this?

thanx

Admant: Any hint on how to solve this?

Disconnect the Arduino before restarting.

Did anyone find a solution? I have the mega2560... but yup Mac startup problems... the white screen and freezing Mini Mac OSX 10.6.8 when it's connected to USB. Did anyone find a solution. It's a problem since i have to make a remote sceduled startup and shutdown on the Mac.

Same problem, OSX 10.6.8 and UNO R3. [added] It's a macbook pro, the 2010 version.

(just participating in the poll, not really a problem for me since I can follow James's "procedure")

I just connected one of my Uno R3 boards to one of my Macs, running OS/X 10.7.5, after shutting it down. It rebooted OK.

I'm reopening this old thread to confirm the issue: Macbook Pro late 2009 with Mac OS 10.6.8 and Arduino UNO connected via USB. The Mac freezes on boot. So, the problem seems to be related to the OS version.

2020 Update:

UNO etal hangs at plain white screen on 2009 iMAC running 10.10.1 Yosemite.

Power down (Hold button), remove Arduino, push button and it's fine.

Replug Arduino and it's all good.

Checked boot order: Only the regular Hard Drive is shown..