Why are my decouplers not working?

[Mitchy]

So i have bought the game yesterday and evrything (kind of..) went alright untill i started a sandbox... i cannot seem to atach the big engines (or the big fuel reserves) to the decouplers...
i just put the decouplers and the engines on it, but when i want to dissatatch the engines the decouplers go boom and the engines just remain... what am i doing wrong? or is it a bug?

[Elementus]

can you show us a screenshot of your ship

[RoofCat]

there are parts that can't be attached to radial decouplers. Like engines or MK1 Crew cabins.
Almost all fuel tanks can be attached to radial decouplers (except maybe this one ). Also all solid fuel boosters ("engines") can be attached to radial decouplers as well.

The issue with tanks and radial decouplers - be careful while attaching. Because you can also attach fuel tanks directly radially without any decoupler. Target middle of the decoupler while attaching to be sure. You can use "2" tool to move up or down later.

[Pembroke]

When placing anything on a radial decoupler your mouse pointer must be hovering on top of that decoupler when you want to click. If the click is going to attach to the coupler the coupler shows green. If the decoupler's not showing green whatever you're trying to attach will attach to something else, most likely to the fuselage.

Mouse over the decoupler. Decoupler flashes green. Click. As RoofCat said you can move the part up and down later with the move tool if it's not where you want it.

[Mitchy]

ye u helped me out, thx

[SportyHeadShot]

Always a fun mistake when launching massive rockets, suddenly your rocket explodes and your scratching your head trying to figure out why lol.