TLDR - object with rescaled parts increases mass with each reload/switch. Bug&temporary walk-around ("fix") report: I have 0.25 fresh install + all mods (most current versions comp. with 0.25 where available). TweakScale 1.47 among them. Everything installed and managed with ModAdmin. Problem as follows - While in VAB Engineer goes whacko with ship mass calculations when rescaling different parts of the ship. After several part swaps Engineer help window just goes blank. In time game crashes when trying to move some rescaled part. At that point it's not that annoying or game breaking. In VAB the bug simply messes up Engineer calculations and you can live with it. However if you finish building a ship (155 part, 300 tons nuclear behemoth + booster) and load it to VAB after fresh game start and launch it, everything looks ok until one of the following: - you reload from save, - you switch to Space Center or any other ship. In my case each reload ended with the mass of the ship tripling, until ridiculous 72900 tons after several switches. Even after first reload my deltaV dropped from over 3k m/s to less then 1k m/s, engine thrust and ISP remain unchanged. It's only problem with mass. After couple reloads without burning any fuel you're down to less then 1 m/s and TWR dropping from 2.x to 0.000x. If you try to drive the ship with altered mass one of three krakens attacks: general - past 50% throttle parts start flying off the ship like dandruff, when coming from inside (cargo bay) they explode the ship from within, gyro - past 50% throttle ship starts oscillating wildly and disintegrates, "warp" - it is possible to drive the ship slowly under 50% but a while later player's point of view is teleported away accelerating rapidly after which game crashes. The higher the mass change, the faster ship explodes under full throttle. With TWR dropped to 0.000x and full thrust applied ship just sits there next to faring and rips itself apart due probably to uneven forces being applied to various parts. Solution: Reverting back to 1.44 solves the mass problem, but is not a 100% fix. After reverting to 1.44 a ship which should have 300 tons still shows as 27900 tons in tracking (saved under 1.47), but when you switch to it normal mass is restored/recalculated properly and when you switch back to tracking it also shows correct mass. Some parts however vanish and stuff that was attached to them drifts outside the ship. After going to VAB and reloading ship saved with 1.47 the model loads without crash, but the same parts that were missing from "live" ship in orbit are also missing from the ship loaded in VAB from file. Ship in VAB is "frozen" - parts attached to the vanished part just hang in the air. You can pick them up, add the missing part and reattach them. Ex.: I've placed lot's of scanning and science equipment inside a cargo bay on two girders operated by two IR hinges. After going back to 1.44 the rescaled girders vanish, leaving all science equipment floating in mid air. In VAB they just hang there. In space they flow outside of the ship, sometimes exploding on collision. So going back to 1.44 solves the mass tripling problem, but may cripple ships you've built while using 1.47.