KSP version: Windows 64-bit, it's Steam
A detailed explanation of what happened and what you were trying to accomplish:
when I upgraded from 1.0.4 to 1.0.5, the Small Hardpoints are separated from the ship body, and side fuel tanks/engines are gone after detached from the ship body,but it was intact from 1.0.4.
I didnt install any parts mods, only mechjeb and other populer mods installed,so I will say it is unmodded problem, problem is probably in the redesign of Small Hardpoint.
A screenshot of your craft or any relevant screens
the first one with 4 side engines connected by small hardpoint is the screenshot in 1.0.4
the second one is the screenshot in 1.0.5, small hardpoint is detached and side enginesare gone.
A .craft file or save files if relevant
here is the saving file: this issue is found in Chen Du profile
https://app.box.com/s/zk97ie4590kwvxlc8f9clkmnwdtv34ft
The ouput_log.txt or player.log file KSP creates when it launches and, if applicable, the crash log KSP has generated when the program crashed
https://app.box.com/s/fgmczfjr6v6jqmae3h011d5azlo9bto7
A detailed list of system specifications
OS: Windows 7 Service Pack 1 (6.1.7601) 64bit
CPU: Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30GHz (8)
RAM: 8140
GPU: NVIDIA GeForce GTX 760 (1991MB)
SM: 30 (Direct3D 9.0c [nvd3dum.dll 9.18.13.5012])
RT Formats: ARGB32, Depth, ARGBHalf, RGB565, Default, DefaultHDR, ARGBFloat, RGFloat, RGHalf, RFloat, RHalf, R8
Are you running a clean installation, or have you updated and some of your persistence or craft files might be older versions, if so which version(s)
from 1.0.4.861 (WindowsPlayer)
to 1.0.5.1028 (WindowsPlayer) Steam