There's a new version 5.4 out now. Just press the 'Install' button near the LR icon in the apps list under the `Search new apps'-bar of the CC desktop app. It seems like a common update process. After the installing process, LR appears in the apps list again as version 5.4 and with a green hook as updated.
Thank you, John. Ended up reinstalling LR 5 and it is working properly. Very strange however.
First, I tried removing the OPM.db file. No help
Second, I reinstalled the CC app. No help.
Third, I reinstalled LR 5. This worked.
mijoo69, thanks. Will try to remember your suggestion next time. I had already updated PS and Bridge so I knew the updates were out there. Anyhow, seem to be in good shape now.