10.6.5 won't let me install
"An error occurred during instillation"
and then
"The update could not be expanded ... will be done next time software update runs. Restart you computer"
I have tried downloading both the regular update (600Mb) and the combo update (900Mb). Both take appropriately long to download but then the dmg file can't be mounted due to a "checksum error". If I transfer the file to another mac on my network I can mount it from there (????) but then get a similar error to the software update above.
I have tried Repairing Permissions and Verifying my boot disk. I have tried a Safe Boot. This happens on both my iMac and Air. I have tried on three separate days.
It strikes me this is a corrupted download file, but then how can everybody else be managing?
Any ideas?
iMac 24", MacBook Air, Mac OS X (10.6.4)