[meldexter]

In my file manager, I have 2 files Add Ons16.db and Add Ons19.db. A web search to resolve a problem suggests these might be to blame and should be removed. From the Wiki I see that these files store Add On including skin settings. Firstly, does having 2 similar files cause problems? Secondly, what will I lose if I delete them both? Advice appreciated.

[ironic_monkey]

the number is the version of the database. so you have two copies, an old v16 and a new v19 (it has been upgraded). having two versions cause no harm, only a single one is used by a particular kodi version.
they contain the listing of the registered addon repositories, as well as blacklisting and such. you don't really lose anything that isn't reproducable by relisting the repositories (apart from any blacklisting you have done).