photos

Is your Photos Library syncing with iCloud Photos?

You wrote " my managed library is on my Mac" - do you mean it is on the internal drive or on an external volume?

If the library is on the internal drive, is it in your Pictures folder or in a different folder?

The library must not be in any folder that is syncing with some cloud serve - you must not keep it in a Dropox, on Google Drive, on iCloud Drive, and if your Desktop or Documents folder are syncing with iCloud Drive, you must not keep the library on your Desktop or in Documents.

Have you checked, if one the albums are empty, or is the library completely empty? Are you seeing any photos, when you click the Library item in the sidebar and then click "All Photos"?

If the library is completely empty, you may want to check, if Photos has opened the wrong library. Quit Photos, if it is running, then hold down he options key ⌥ and launch Photos again, while holding down options. release the key, when the dialog to select a library appears. If there eis more than one library, try all in turn.

Please read the following user tip and restate your question/problem in detail: 

     Writing an Effective Apple Support Communities Question - Apple Community

What Mac model and year are you using?

What system are you running?

Where is your library located? If on an external drive how is the drive formatted and connected to your Mac.

Are you running a "managed" or "referenced" library?

How much free space do you have on your boot drive?

Are you running iCloud Photos? If so do you have Optimize Mac Storage enabled?