Screens go blank (blue, actually) when external monitor attached

[myawn]

This has just started happening on my PowerBook G4 + 24" ACD combo ...

Now, if I plug into the external monitor while the laptop is running, I just get a solid blue screen on both the laptop screen and the external monitor. If I disconnect again, I sometimes will get the laptop display back, but other times it just stays solid blue.

Anyone seen this happen?

Running the latest 10.4 update.

 

[digitalpencil]

Sounds like display preferences isn't correctly detecting the new screen. Try hitting F7 to switch display modes and see if that refreshes the displays correctly. If not, all I can think of is to shutdown, plug in the monitor and boot. What happens if you try this?

 

[myawn]

Sounds like display preferences isn't correctly detecting the new screen. Try hitting F7 to switch display modes and see if that refreshes the displays correctly. If not, all I can think of is to shutdown, plug in the monitor and boot. What happens if you try this?

Rebooting while attached to the monitor was working fine (both displays came up normally).

After doing that, I noticed that 'mirror displays' was turned on -- not an option I generally use, and I'm not sure how it got set. Turning it off appears to have fixed the problem, now I can dock and undock and the external display comes up as expected.

Strange, but seems OK now.