has been my choice of password-manager for years and it has never failed to deliver. Recently, after updating to Firefox 37.02 the Lastpass addon started showing error as below. Clicking the `Ignore` button made the error go away with no consequences to the functionality of the utility, however this was annoying and I got it fixed by upgrading to a new PRE-BUILD of the Firefox as shared ahead.
(for info on how your program caused an assertion failure, see documentation, etc)"
Luckily the solution was simply to get the latest addon version from - https://lastpass.com/lppre.xpi, as per the posting their community forum "this was likely a consequence of a recent compiler upgrade."