Kerbal Space Program

Of course, sorry for the lack of information given at the beginning :)

I'm playing vanilla KSP through Steam, I believe it is the x64 version, and a game restart hasn't changed anything. I was able to replicate it in sandbox and career mode, as mentioned below.

I first noticed it in career mode, I accepted a contract to put a wheeled outpost supporting 9 kerbals on the mun. other requirements included it have a science lab, power, antennae, and the infamous docking port. After accepting the contract, I researched Advanced MetalWorks (possible grammar error there? I dunno), giving me access to the necessary clampotron. I built the craft pictured in the screenshot, and promptly launched it, when I first noticed the bug. I wrote it off as a fluke, and restarted the game. I went to launch it a second time, and it told me that I had an invalid part (the same error message you would get if you tried launching a craft using an experimental part after the contract was completed). I went into the VAB, removed the clampotron, spawned a new one, placed it on the craft, and the game let me launch. This became the only way I was able to launch a craft containg a clampotron. When the launch pad loaded, the bug reappeared. I followed the restarting process a few more times, all with the same result. When I went to write the bug report, I discovered that I could replicate it in sandbox mode. Further testing revealed that all other craft launched as normal, but as soon as i added a clampotron, the bug appeared.

Long story short, you folks are awesome, and thanks for your patience with a first-time bug reporter.

Screenshots and log: https://www.dropbox.com/sh/wax8cp6yh5vjn4t/AADbTfOiXHYau6Qpqb6oC44ja?dl=0

Thank you for your further information, and you're welcome :)

The symptoms you describe are similar to what I have observed in #3929, and the missing part message would suggest that the craft is in some way corrupt. However, the log reveals you have mods installed and furthermore there is at least one conflict with the versions. This may be the root of the corruption.

We are unable to support mods and plugins as there are so many, and so many versions to keep on top of. Please could you review your installation and ensure you have the most up to date versions. Module Manager 1.5.6 in particular is quite old now, and would indicate that it comes embedded with another possibly old addon. A list of 0.90 compatible addons is maintained on the forum for your information.

If the problem persists after you have removed the mods, then please report back with your logs and any other information. Removal and reinstallation of the mods with care to use the latest and compatible versions is good practise regardless. Please report back if the problem is solved too.

With a complete wipe of the game files (keeping the save game I was using), and a fresh, clean install, the bug is gone! Thanks for your help, Squelch, and keep on rocking the bug fixes :)