I tried to open/sync a facebook account with a king (? - played on my desktop) account.

But after the attempted sync, I lost my boosters on my desktop as well. 

Hi Melissa-  Thanks for posting on King Care. Are you playing between Facebook and King.com or mobile and desktop?

Boosters are currently non-transferable between platforms and devices.As they are items saved directly to your device's memory they can only be used on that specific device.

This means that if you receive them on your mobile device you are unable to access them on your PC and vice versa.

Your Gold Bars and level progression will always be synched and saved between your devices, as long as you are connected to our Kingdom or Facebook.

I hope this helps :-) 

Let me know if you still need a hand. 

After the attempted sync, I lost all boosters and memory pieces on my desktop as well.