Editor4.8.1 stuck

I have download the Open World Demo Collection.I learn use it from Telling the Spawner what to Spawn

In the section 6:Use the search menu to locate HillTree_02 Static Mesh from the Open World Demo Collection by typing HillTree_02 as the search term and load it by clicking on it,But after that operation,my UE editor stuck,can’t work.I Have to kill editor from the task manager. Who met this situation?

MEEEE TOOO! help!

i tried ScotsPine_01 and waited a little, then it worked.