Fatal errors after upgrade to 3.8

Hello, after upgrading to WordPress 3.8 ans some plugins I could no longer get in the admin part of my site, fatal errors after admin login screen. (the site itself worked perfectly well)
The solution was to open the site in ftp, cut all the plugins, paste them in a temporary folder on the local PC, open the admin site (that had then no longer fatal errors), paste the plugins back in the plugins folder through ftp, and activate them one by one. Some backup plugins and traffic manager caused the problems, impossible to activate them. No problem (anymore) except that I have no more backups (except manually through ftp of course) and that at least one of the backup plugins (wp complete backup by MyCodetree) cannot be removed; deleting it again gives a fatal error. Mycodetree seems to no longer exist so I will have to live with a deactivated plugin in the list. Maybe this solution is helpful to other also.
Happy new year
Ronald