Hi there,
I've seen this has happened for quite a few people but wanted to post myself to further add fire to ACER/Microsoft.
After spending hours doing the upgrade I discovered (like others) that my mouse did not respond. I went into the options and enabled ELAN and it moved, but could not click anything.
This is possibly the most annoying/biggest waste of time possible. Especially considering I received an email from Acer last night advising me that windows 10 was ready for me and my device. Clearly they are NOT.
ACER can you please fix this now. Especially considering you are encouraging your customers to upgrade. It's one thing to find a bug, it's a whole other thing to encourage them provide absolutely no resolution.
After being an ACER customer (laptops) for many, many years, it does make me think about other, more organised brands that respond.