Please close lightroom.
Go to your Pictures>>Lightroom folder and see if there is a file with the same name as the catalog with a ".LOCK" extension,
Delete that lock file and reopen Lightroom.
there is no lock
Refer to link below.
This should fix it.
If still the same
2>>When starting Lightroom, hold down the Ctrl key (Win) or the Option key (Mac).
This will present a dialog allowing you to choose the catalog you want to open.
Select your catalog, check "Test the integrity of this catalog" and click Open
3>>Backup your Catalog First
copy paste your catalog from location.
Try Resetting Preferences
Hold down CTRL, ALT, Shift(Windows)/Command,Option Shift(MAC) while starting up Lightroom
4>>Reinstall Lightroom after running Disk Permission repair
The steps in the link did not fix the issue.
The steps in your Step 2 also brings up the same window when presented with the unexpected error message allowing to me select the catalog or create a new one.
Under 'select a recent catalog to open' it lists the latest catalog
Lightroom Catalog,Ircat E:\Pictures\Lightroom (where the E:\ drive is a 3rd hard drive in my computer).
My options are to Choose a Different Catalog and Create a New Catalog as mentioned prior.
However, selecting a different catalog does nothing and it continues to show the catalog listed above as the one selected.
And selecting Create a New Catalog also does nothing. I still get the same error message as prior.
Attempting 'Test the integrity of this catalog' also throws the same error.
Attempting to launch Lightroom with CTRL, ALT, Shift only brings up the Lightroom.exe Properties window but does not launch Lightroom
In your 4th step you say to re-install Lightroom after running Disk Permission Repair? Where and what is Disk Permission Repair
How does one get support for this issue?? This is a work stoppage.
I had the same problem. Right-click on LR icon and open as administrator. The integrity of the catalog is checked and LR opens up without any error messages. Hope this helps.
That does not work