Hi everyone! Just registered to tell you that all of your fixes did not work for me But, I did find a fix myself by just messing around, the fix goes like this:
Here are all the comands
reboot
ifdown (interface)
airmon-ng check (kill them all!)
airmon-ng start wlan1 (in my case)
Now it started on mon0 but wlan1 is still up
airmon-ng stop wlan1 (mon0 is still up)
wash -i mon0
That worked for me, oddly, but hey, it works! Also, you will have to do this everytime you run wash.