If you need to set up mirroring...

... on SQL2005, SP2, before the rollup-fixes released afterwards, you need to

1) backup the primary
2) restore the backup on the secondary
3) shrink the primary's transaction log file
4) run a differential backup, and restore that to the secondary
5) run a transaction log backup and restore *that* on the secondary as well, then
6) set up mirroring.

If you think "I don't need a differential, I already have a Transaction Log backup", or if you think "why would I need a transaction log *after* I take the differential?" don't. Just stop that thinking *right there*. Just do it.

Trust me.

RazzfrazzinFOURHOURSrazzafrazzinShouldaBeenAQuietAFTERNOONrazzafrazzaSQL....

If you need to set up mirroring...

... on SQL2005, SP2, before the rollup-fixes released afterwards, you need to

1) backup the primary
2) restore the backup on the secondary
3) shrink the primary's transaction log file
4) run a differential backup, and restore that to the secondary
5) run a transaction log backup and restore *that* on the secondary as well, then
6) set up mirroring.

If you think "I don't need a differential, I already have a Transaction Log backup", or if you think "why would I need a transaction log *after* I take the differential?" don't. Just stop that thinking *right there*. Just do it.

Trust me.

RazzfrazzinFOURHOURSrazzafrazzinShouldaBeenAQuietAFTERNOONrazzafrazzaSQL....