The first test you can run is called Table Verification. This works by checking your actual Form Tools database structure with what it should be. It then generates a log of all successfully tested elements (tables and columns), and provides a list of elements that failed. These errors include:
- Missing tables
- Missing table columns
- Invalid table columns: contain the wrong information
How to use
This test is exceedingly easy to use. Just install the module as usual (see instructions here), then go to your Modules page and select it. Once in the module, you'll see a list of components that have provided information about their database structure. Select those components you want to test (all are selected by default) and click the Test button. That will generate success and error logs of what it finds.
What it DOESN'T test
This module currently only tests the database structure. It doesn't test the semantic content of the tables; i.e. it doesn't confirm that the tables contain the data that's expected. Likewise, it doesn't test your custom form tables to confirm that the fields and data in those tables match the data stored in your main forms table.
Don't panic! This is a good thing! I mean, sure, ideally there would be no problems, but now at least we now know what could be leading to any number problems with your installation.
If the module finds a problem with your tables, first check the Common Problems page. If you don't find your problem listed there, you'll need to post your error logs on github. The Table Verification test only identifies problems - not fixes them. This is by design: we want to know what problems people are running into so we can figure out what happened and find patterns in the problems. But also, we don't want to execute potentially harmful "fixes" to your database without fully understanding them first.