We copy our current project frequently to other computers, create backup-copies or move it around on one and the same computer.
We noticed that Unity sometimes needs to re-import the entire project (and thereby update the cache?) and sometimes it doesn't. Copying on a Mac f.i. seems to work without re-importing, while copying on Windows does...
Our project has grown quite big recently and the re-import takes a while, so I'd be very interested in a way to copy without having to re-import. Is it a thing about absolute paths or meta data hidden from the explorer/finder?
Well if you have a PRO license you can use version control like SVN or whatever to do this "transferring" to other computers. The PRO license is almost worth it just for the fact that you can use external source control.
Here is a unity help document to tell you how to set up the external source control once you upgrade to pro.
If you aren't upgrading to PRO I have heard of people using DropBox as simple source control for non-pro unity projects, although I don't think that I would trust dropbox to do that for myself.
We have the unity pro and source control liscense and still have the same issue…its alot of work especially for an indie project…Source Control should work like Perforce…
In our case, the clients had to uninstall everything Unity and rebuild from scratch, then sync up to the server, which was at least 4 hours.