Translation after Update disappears

..it depends how you created those custom translations: https://localise.biz/wordpress/plugin/custom-translations

But how is it possible at the wordpress Loco Plugin to set this specific folder as default?

This is not necessary. You just save your files in the custom location. This is explained in the section on loading order from the first link you posted.

You’ve not said whether you have a problem with files in this location, but if you do, see the FAQ: https://localise.biz/wordpress/plugin/faqs/custom-folder

Thanks! I got it. Every translation is still there after an update.
The Link https://localise.biz/wordpress/plugin/custom-translations is very helpful ??
Same is explained on loading order. Perfect.
I have no problem with files in this location.

Just for understanding: if i create my own template in an individuall language, the theme or plugin always takes this file first (which is not changeable via update by wordpress or theme or plugin) and adds/ join together missing words from the system file?! Is that what running sync means/ or the Button Sync when you are inside the translation?

At the moment i also don′t understand the different files (po, pot, mo) and their specific job.

Furthermore i don′t understand why it′s not possible when i created my own indiviual custom language file, that it is not possible to chance the original language (which is english)? Because i also want to chance some words in english.

BR

Just for understanding: if i create my own template in an individuall language, the theme or plugin always takes this file first

You don’t mean template. A translation file is not a template.

(which is not changeable via update by wordpress or theme or plugin)

If it’s in the custom location, yes.

and adds/ join together missing words from the system file?!

This is what Loco Translate’s loading help does, yes.

Is that what running sync means/ or the Button Sync when you are inside the translation?

No. the runtime (loading) functions have nothing to do with the editing and syncing functions. To understand file syncing see the manual: https://localise.biz/wordpress/plugin/manual/sync

At the moment i also don′t understand the different files (po, pot, mo) and their specific job.

See https://localise.biz/wordpress/plugin/manual/templates

Furthermore i don′t understand why it′s not possible when i created my own indiviual custom language file, that it is not possible to chance the original language (which is english)?

The “English” phrases you see are unique identifiers. Don’t think of them as a language, they are “source strings” and they must not change. It is possible to create English translations that you like – just create a translation file in English.

okay, thanks. this helped a lot ??