The USB with the GEL file is regonised but the OK screen to allow processing of upgrade does not appear. Instructions for upgrading Core Electronic website followed.
Welcome to the forum
Once you’ve received your provisioned upgrade codes from Rigol and entered them into their website tool it should just be as simple as adding the GEL file you receive to the ROOT directory of an otherwise blank USB and following the prompts.
We have had customers in the past find one of their USB sticks wasn’t working properly and trying again with a different brand USB stick fixed the issue.
Perhaps try again with another USB if you have one handy and just double-check that the GEL file is the only file on the stick.