Cannot select multiple items in hierarchy / scene?

For some reason, sometimes Unity seems to “break” and I can’t select multiple objects in the hierarchy or scene. I shift click two or more items and they highlight for a second, then immediately unselect themselves. If I use the marquee in the scene view and drag it over a few objects in my scene, it will only select the object that’s currently selected in the hierarchy instead of all the ones I dragged over.

Whenever this happens as well, I can’t use the vertex snapping tool. I press v and it puts the cursor over the vertex, but it can’t find any other vertices in the scene to snap to. This is really annoy and is hindering my progress on my current project. I did lots of google searches and couldn’t find anyone with this problem, but it happens on BOTH of my computers, but PC and Mac. Any ideas?

[SOLVED] I have found the solution. On the top right there are 4 dropdown boxes, click on the one labelled “Layers” then within that turn off “UI”. After that, you will be able to select multiple objects by pressing the ctrl + clicking the objects. Turning this off and on doesn’t affect anything in-game it only changes within the unity scene view.

Try control clicking them.

I got this same issue today. I found that it only happens if one of the objects I’m trying to select has a 2D Toolkit sprite attached. I asked the creators of the toolkit about it and they said they’ve had other similar reports and are looking to fix it.

This happens to me while using Synergy client mode, if you’re using it, just take a directly keyboard instead.

Hope this helps someone,

on the Hierarchy: you select multiple objects by holding Shift then clicking the items you want to select.
on the Scene: you can select adjacent multiple objects by dragging a square surrounding them.

Haven’t found a way to select un-adjacent objects on Scene like on Hierarchy

Thank you Zhuchun. Synergy was also my issue !!!