Local Encryption settings for a database do not change
After changing database encryption settings from "Locally encrypt this database" to "Do not locally encrypt" you find others are still unable to access the database.
A user tries to open a database and receives the message:
"The database has local access protection (encrypted) and you are not authorized to access it."
In one particular case, even though "Do not locally encrypt this database" was selected, the description at the bottom of the encryption settings box read as if encryption was enabled.
This can occur if COMPACT has not been run on the local database. If a change is made to the database encryption settings, a COMPACT must be run.
Resolving the problem
Open the database in the Notes Administrator Client. Using the ID that had the database locally encrypted, go to Database Properties -> Encryption Settings. Select "Do not locally encrypt this database" again. (Notice that the description below may immediately change.)
Next COMPACT the database. Go to the Database Properties -> Info tab. Click the "Compact" button. Close the database if it is open.
Once the COMPACT runs, the new encryption value is honored.