I updated two machines to 10.5.4 a few weeks ago and Expose has become affected on both of them.

One is a 2006 white Core 2 Duo 2.16Mhz iMac. The other is a 2007 alu Core 2 Duo 2.4Mhz iMac.

On both machines, I have Expose set up as:

• All windows: mouse button 4
• Application windows: mouse button 3
• Show desktop: secondary mouse button

Both have Mighty Mice.

On the white iMac, mouse button 3 doesn't work. It 'works' in that it can select things in Quark for example, but it won't work in Expose. So I can swap all three settings about, but whatever button 3 is set as, it has no effect.

On the alumnium iMac, the same is true but only the secondary mouse button works. Buttons 3 and 4 have no effect.

I have tried different mice on both machines.

Is there an Expose prefs file that can be trashed?

Update: 10.5.5 didn't fix it and neither did fixing various caches etc. in Onyx