Sometimes you may find that your clipboard on your iMac is doing strange things. Here’s how to clear your OSX clipboard and reset it back to empty. This has been confirmed to work on Leopard through to Yosemite. Later versions it may still work (or not).
Edit – This applies to any Mac running OSX and is not limited to the iMac
Open up a Terminal Window
Type in the following Command and press return
echo -n '' | pbcopy
Test by pasting somewhere (nothing should be pasted)