How can I know the branch of all my folders in tortoise SVN?

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Hi all,

I have to switch and merge my project from a branch to the trunk and vice versa, but tortoise says me: Cannot merge into a working copy with a switched subtree.

I working in a project with about 400 subfolders. I know that I made some switches into some subfolders, but I cannot remember all of them. I think I'm working into the same branch but it don't must be sure. Now, trying to merge two branches, I have the error above mentioned.
There is a method to know where are versioned all my folders?

What I have tried:

I tried to check for them a single folder I remember I switched, but I didn't found no errors. Are all of them into the same branch. I tried to check for some other folder, but it need a lot of time each. I need of a quicker way.