VoidSquid

To avoid such unfortunate situations in the future, I suggest you follow these basic guidelines:

Sounds right, yes. I can't test this tough as I've reverted to KSP 1.10.1.

Most commonly caused by an incompatible mod or a mod conflict. Try to isolate the mod causing this: remove half of your mods, see if KSP loads. Yes: re-add half of the removed mods, try again. No: remove half of the remaining mods. Repeat until you find the mod causing the issue. I'm wondering though, in your mod list I see two lines for Kerbalism?

The flag problem is a confirmed bug https://bugs.kerbalspaceprogram.com/issues/26872 About the ladder issue, I don't know, maybe other fellow Kerbonauts can add add something here.

Clicking the building directly doesn't work as well? And did anything change in your installation which might cause the issue, mod updates?

All right... and how about uninstalling KSP 1.11.0 (I assume @pijamaman5 has installed the latest version) and installing 1.10.1? Logfiles? Modlist?

Question: what are the keys / key names for Shift = increase and Ctrl = decrease throttle in French, maybe those keys do work and bring us closer to a solution?

Weird problem it is. All right. then let's see that we hopefully can solve it tomorrow.

And what about a new KSP 1.10.1 installation?

Didn't @Xemina already check this? I'm still not sure, could/did @pijamaman5 increase (maximize) throttle? If yes, result? At any rate, the probability of KSP, properly installed, simply doesn't work for just a single user, is pretty close to zero.

If I understood this post correctly the issue is a general one, not just this rocket. Hence it is tied to the installation itself, that why I suggested to install a different KSP version, 1.10.1 is matured and known to work fine. I really, really want to help solving this mystery!

OP provided a link to print screen here Hopefully you can help solving this issue, @Okhin, I don't have any further ideas atm, and obviously we do have a language issue here. Thank you!

A final idea/suggestion, if I may, requires very little time and work: You mark the existing BBT 1.9.1 at Spacedock as compatible with KSP 1.10.1 Then add a line to the changelog and upload the mod again to Spadedock, this time telling Spacedock that the new upload is BBT version 1.9.2, being compatible with KSP 1.11.0 Result: two mod-wise identical uploads, but with different version numbers for different KSP version. And no need to tinker with any .version files at all.

Odd and odder... Can you try to completely uninstall KSP and install the older version 1.10.1? Also, did you build the rocket yourself or downloaded it from somewhere?

Glad to hear, excellent

I do remember once helping a guy on Twitch with a similar problem, turned out his KSP installation was buggy, a Steam file verify did solve the problem for him.

@Xemina I was wondering, the screenshot @pijamaman5 provided didn't show the SRBs active, no flames, no exhaust plume. Did he active the 1st stage by pressing space bar?

If you installed the mods via CKAN, you can uninstall them from there too. Else you'd have to manually delete all unwanted mod folders under GamaData. Leave the Squad and SquadExpanions folder there. For your save games, delete the respective folder(s) in the subfolder saves. Might be a good idea to make a backup before you delete stuff, better safe than sorry.

Chances are that you simply can ignore that warning, just try it out.

Getting some log spam: [ERR 09:15:51.773] ContractConfigurator.ContractType: CONTRACT_TYPE 'RoverExplore': Error parsing hasScientist followed by various NRE lines The contracts themselves work fine though. RoverMissions 0.1.7 (installed manually as compatibility is only for KSP 1.2.2) , CC 1.30.5, KSP 1.10.1

Doesn't work too if you click on a building directly, i.e. not via the menu icons? And did anything change in your installation which might cause the issue, mod updates? Might be an input lock, you can try @linuxgurugamer's Click Through Blocker which also provides a button to clear all input locks.

Glad I could help, you're welcome! Besides, welcome to our forums, always nice to see new players around, joining for a trip to the stars. Don't hesitate to ask questions, people here are happy to help!

In addition to what @goldenpsp already said, you can also install the dev version via CKAN if you enable the respective repository in the settings menu: CKAN, in case you don't know yet, is THE KSP mod manager, highly recommended! You can find information how to use and install it here: https://github.com/KSP-CKAN/CKAN/wiki/User-guide

It's a confirmed bug, yes. https://bugs.kerbalspaceprogram.com/issues/26872

That's hard do believe... see, I'm working as Windows system engineer for 25 years, and this is one of the most common issues users have, we deal with such stuff on a daily basis. For Windows 10, if you both disable UAC (Slider down to the lowest position) as well as disable the setting "Run all administrators in Admin Approval Mode" (either via GUI usind gpedit.msc, or directly in the registry) there can't be any more such warnings preventing you from deleting a folder. Of course, a reboot may be required after changing these settings. In general, I recommend to install and run KSP not in a folder below Program Files or Program Files (x86) but for example in a folder like D:\KSP, this way avoiding any potential interference from Windows.