Welcome aboard!
That warning is simply letting you know that not all of your changes were captured by that layer.
So if you had five items that changed, the capture was canceled after only three of them were captured, you later rewind to that layer and restore that layer, you'll have two items missing or they'll be older (previously captured) versions?in other words, not the versions that existed when that layer was captured.
When you start the next capture, QRecall will (always!) pick up where it left off capturing the two items that didn't get captured in the previous layer. And if you want to be tidy, merging those two layers will result in a layer that is complete and up-to-date and effectively nullifies the warning your received on the first layer.
To recall an item (or items) from the archive, you can simply drag the item from the archive back to your hard drive like a Finder copy.
The "Restore" command does much the same, but instead of you deciding where the recalled copy goes, you simply select the items in the archive; QRecall finds the original items and replaces them with the restored version.
I hope that helps. Please post any additional questions you have or send them to
suppport@qrecall.com