Cattette

Foreign keyboards should still work. My Swedish keyboard can switch between vessels with the 'å' and 'ä' keys without me even having to change any settings. You know when you've spent too much time on the internet when you call your own native language "foreign" :p

I'd suggest posting this question on the forum page for the KAS mod instead of starting a new thread. I think your question would be answered more quickly there.

Windows antivirus and other antivirus softwares can act funny if Mechjeb is installed for some reason, causing this very issue. This could be avoided by simply installing KSP outside the C:\Program Files (x86) directory, Steam has an option to change the directory for where game files gets installed into, but you should be able to just move the KSP folder anywhere and not face any issues with that, just keep in mind that if you decide to move the KSP folder yourself then you cant launch it through the Steam app, you'll have to make a shortcut to the KSP executable and put in on your desktop or taskbar. You wont need to do that if you ask Steam to change the installation folder. If this doesn't solve your issue then let us know.

The most efficent is probably just a ISRU unit with a docking port and solar panels in orbit. While a drill on the surface with solar panels and a engineer Kerbal in a command seat operates on the surface. Both the orbit and mining site would ideally be placed equatorialy. You may wish to have both the extraction and refining take place on the surface, while this isn't any less efficent than having the ISRU unit in orbit when it's all set up, you will have to haul the ISRU unit down to the surface of the moon which will ultimately cost more DV in total.

The Luna Multiplayer mod likely came pre-packaged with some or all of its dependencies. Module mMnager is an example of a mod that a lot of other mods require, and mod makers are generally allowed to include Module Manager in their files. If you open your gamedata folder inside your KSP folder and the one in the mod download folder you'll likely see a few folders and perhaps a few .dll files. Your system is likely warning you about overwriting these when it gave you that error. Simply move over the individual files and folders from the downloaded gamedata folder to your ksp/gamedata folder that arent already there.

I've had this issue since time immemorial. Every time i start a new install it resolves itself, but when i start adding some mods it appears again. I do recall once managing to track down which mod was causing this issue, but it was a pretty vital mod that i feelt was worth the keybind trade-off. I do not remember which mod this was, but you should provide a mod list.

The RP-1 fuel tank system is a bit all over the place. The fuel tank you get from the start are called seperate structures. Once you get some new tech you should be able to right click this tank in the VAB and switch material to aluminium, which is lighter than the default material. Once you advance further in tech you'll be able to unlock integral tanks, these should appear as seperate parts in the VAB, and they are way lighter than seperate structure tanks. In conclusion, the earliest uppgrades you should be able to apply are available in the part menu of your seperate structure tanks.

You need part tools for Unity: Follow this well made tutorial:

Did you follow the installation guide on the RP-1 github wiki verbatim?

Images need to be hosted on 3rd party sites

It is required to give a lot of stock and modded parts reflections. TU does nothing on itself, it only allows parts to use more powerful materials. You need another mod that actually tells stuff to be reflective.

Do you have Magpiemods installed?

Would it be significantly more efficent to cheat and ignite the LR105 engine when you're done with the LR89s?

You seem to have already tried everything that i would suggest to fix this issue, i can't really help you in that regard. But i must point out that you can have multiple instances of KSP from Steam. All you need to do is to rename the Steam-installed KSP folder to something else than "Kerbal Space Program", this will prompt Steam to install a fresh copy of whatever KSP version you want, and there will be no kind of lock blocking you from running a ksp.exe file that isn't registered with Steam directly I do this and it works flawlessly for my RSS/RO/RP1, general modded, and dev builds of KSP. Also I do think that you failed to upload your images correctly. They need to be hosted on another site.

What parts does this happen to? And what mod are they from? Can we get a complete list of mods you have installed?