[ext23]

I have just copied all my media from a 3TB drive to a 4TB. The file trees are the same on both drives.

How can I batch update the library paths so that everything points to the 4TB drive rather than the 3TB drive?

[wsnipex]

the easiest is the mount the new drive on the same mount point as the old one.
OR: rescan library
or: path substitution in advancedsettings.xml
or: replace all paths in the DB