Black screen at starting budgie since update

Hello,

i have a recycling an old portable with ssd but the graphic card hd3470 with the résolution limited to 1024X768
Since the update to the version 18 and above , i have a black screen at tha starting budgie . but when i starting in the rescue/debug mode , i retreive the normal screen .
==> i suspect the system is booting in resolution to high for my computer or the graphic driver isn’t appropriate
Can you indicate me the option or file to change to force only in 1024X768?