Without the traceback nobody can name your exact cause, but "module does not install properly" in Odoo is almost always one of these, in this order:
1) Get the real error first. Start Odoo from the console with the module update and watch the log:
odoo-bin -d yourdb -u your_module --stop-after-init --log-level=debug
The first ERROR/Traceback block is the one that matters - everything after it is just fallout. Post that block here if the steps below do not fix it.
2) Manifest problems. In __manifest__.py check: "depends" lists every module your models/views inherit from, "data" files are in the right order (security/ir.model.access.csv before views that use the models, data files before views that reference their records), and the version targets your Odoo series (a 16.0 module on 17/18 commonly half-installs).
3) Python import errors. Every folder needs __init__.py importing its files, and models/__init__.py must import each model file. A single forgotten import makes fields/views silently missing instead of failing loudly.
4) XML external IDs. "External ID not found" or "ParseError" during data loading usually means a view/record references an xmlid that is defined later in the data list, in a dependency you forgot, or with a typo in the module prefix.
5) Access rights. If it installs but menus/models error on open or stay invisible, you are probably missing ir.model.access.csv rows for the new models.
6) API changes between series. If the code was written for an older Odoo: attrs= in views was removed (17+ uses invisible/readonly expressions), some decorators and field parameters changed names, and _sql_constraints syntax moved. Version mismatch shows exactly as random install weirdness.
7) Stale state. After fixing code, update the module list (Apps > Update Apps List in debug mode) and run the -u update again; a half-installed module sometimes needs to be uninstalled first so its data reloads cleanly.
Share your Odoo version, how you installed it (source, docker or package) and the first traceback block from step 1 - with that, the exact line can usually be pointed at directly.