Today I updated my Allview Viper L to 4.4.2. Up untill this point the "Unfortunately the launcher has stopped working" message would appear only when I would try to edit the Desktop. After the update it kept on appearing. Rebooted the phone, powered off and on, took out the battery but the error still appeared.
HOWEVER, I noticed that tapping and swiping down on the upper side of the screen allowed me to reach the Settings. From there I went to System Backup and backed up my data(contacts, call log,calendar etc) to my SD card. Afterwards I went to Backup & reset and tapped on Factory data reset, tapped on Format phone storage and then, finally, hit Reset phone. Now it's working perfectly: it's still updated to 4.4.2, I have all my data, music and the rest
P.S. One reason I think this error appeared is because I disabled some apps and the phone warned me that things may go sideways so....moral of the story: don't disable apps that are already on your phone. Disable only the apps you installed and you are perfectly sure won't affect your phone in any way. Hope I've helped.