I recently updated from Ubuntu 16.4 to 18.4 and after the reboot at the and of the update, the screen blacked out, every time i restart the cpu its the same, just blacks out and i cant even move the mouse. only way o can do anything is access grub and root mode
Essentially, you cannot downgrade an existing Ubuntu system. The only way to downgrade is to perform a fresh install, i.e., an install where you wipe out the existing install first.
A fresh install wipes out all system files, but also the user data if these are located on the same partition. If needed, you may want to save existing user data on your system first from a live session, before starting the install.
but how can i save existing data on my computer if i cant access them directly? After the starting logo the screen turns black and freezes, can´t write or move mouse Aug 30, 2018 at 19:56
The install as I indicated leaves your data intact. However, you should nevertheless saveguard your data first: something always might go wrong. You can do that from a live session. Mount your data partition and copy the relevant data to an external drive.– vanadiumAug 30, 2018 at 20:00
Ctrl + Alt + Fn(where
Fnis any of the function key
F1,F2...)? Also, if possible provide the hardware configuration also it will help a lot to narrow the issue.