I don't know how basic folder disappears. Perhaps, I may delete the folder mistakenly.
As a result, lots of indicator in .afl files like Volume, volume at price, price lose.
How to recover this folder, is it for me to uninstall AB for fixing this issue in order to re-create folder as well as these *.afl files again?
Ooops sorry
I really miss that, as the Op ask "basic folder disappears", but i should get quickly the meaning what he try to say.
i hope @technqvi he moved the folder otherwise as @codejunkie said he have to run AmiBroker setup.
Just re-run setup in "upgrade" mode. It will recreate missing files without changing anything that you wrote. Running in "full setup" will create default "Data" folder (database with US stocks) that you might not want to do (unless you want to recreate default database). That is pretty much the difference between two modes.
Thank you. I wasn't sure anymore if upgrade mode would update dlls and exe files only. That is why I had suggested full setup. I had written update mode at first but then I decided changing to suggesting to run full setup.