HasanMerkit I noticed that some columns belonging to extensions I removed earlier are still in my database. How can I safely remove them? I've done this before. However, when I installed the same extension later, it caused errors.
GreXXL HasanMerkit can you share what extension you are talking about and what error you are seeing when re-installing the extension. Please also share the process you are using to add / remove extensions currently.
HasanMerkit GreXXL for example, https://discuss.flarum.org/d/23741-support-platform-turn-your-community-into-a-support-platform