Hard drive with iPhoto album comes up "locked"

Attempting to open iPhoto after installing new iTunes.

The library is on another drive. I get the message:

"CAUTION

"The iPhoto library is on a locked volume.
Reopen iPhoto when you have read/write access, or reopen iPhoto
with the Option key held down to choose another library."

When I open the Info for that drive and unlock its little lock icon, that doesn't work. It stays locked and will not change. Collapsing the Info window and reopening it shows the locked status again.

What the?