Could you share the version of Lightroom Classic you're using along with the version of Windows you're working on? Did you start experiencing this behavior after an update?
You can try launching Lightroom Classic with Alt key pressed on your keyboard. When the app launches, it should give you an option to select the catalog you wish to open. Select your catalog and check the option to test the integrity of the catalog available on the bottom right. Once you've checked the option, click Open and let us know how it goes.
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