Clone vdi image (.vdi) without the UID error.
Use the below command via terminal.
VBoxManage clonevdi <ImageYouWantToCopy.vdi> <DestinationImage.vdi>
If you get below error, that means one of your VM is using the .vdi image. Shutdown that VM and run the command again.
VBoxManage: error: Failed to lock source media 'ImageYouWantToCopy.vdi' VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component Medium, interface IMedium, callee nsISupports VBoxManage: error: Context: "CloneTo(dstDisk, ComSafeArrayAsInParam(l_variants), NULL, progress.asOutParam())" at line 740 of file VBoxManageDisk.cpp