I did get error 104 when i trying install game. The ticket (https://help.elderscrollsonline.com/#en/answer/2651) said: "At least 125GB on PC and 135GB on Mac are needed to perform the download and installation operations"... but even then i've still get error 104.
I found at \Games\TheElderScrollsOnline\Logs a log file The_Elder_Scrolls_Online_Install_10_29_2023, and there was:
Install Log Detail:
Check Disk Space: \Games\TheElderScrollsOnline
Status: SUCCESSFUL
Additional Notes: NOTE - Required Disk Space:315,786,207 Bytes Free Disk Space:359,539,056,640 Bytes

But at that moment there are wasn't enough space (was about 200GB). So i moved some files to get that 320GB+, and only then successfully install the game. I hope my message will help those who are installing the game again, or for the first time.

And yes, the ticket needs to be updated.