On the evening of 4/18/2017 Koha was updated to 16.11. If Koha is not functioning properly, you will need to clear your browser cache and history.
There are 3 ways to do so (Pick One):
1) (easiest) Run CCleaner (in all programs on the start menu or install from here: https://drive.google.com/open?id=0B4NQOFkOskKoZ0lBOFNscG1Rbm8
2) In Firefox on the menu bar go to History–>Clear Recent History–>Time Range to Clear=Everything–>Check all boxes BUT Active Login–>Clear Now.
3)Clear your Firefox Browser History: https://drive.google.com/file/d/0BwSO_oYghmAxc283WTVNbVI0UFU/view?pref=2&pli=1
AND clear your Chrome Browser History: https://support.google.com/accounts/answer/32050?hl=en
ALSO make to re-allow pop-ups: https://drive.google.com/open?id=0B4NQOFkOskKoMTBxcklSLUl6cG8