did you try with 3.5.0 RC3 https://github.com/joomla/joomla-cms/releases/tag/3.5.0-rc3?

Try disabling the "System - Joomla! Update Notification" and "System - Joomla! Statistics" plugins. If you're on an intranet with no outside connection those won't work anyway and waste a lot of loading time (the stats plugin we have a 2 second coded in to for its HTTP POST to the stats server, the update plugin relies on the underlying updater library which doesn't have timeouts on its HTTP GET requests).

@andrepereiradasilva Yes, the same happens in 3.5.0 RC3

@mbabker After testing in 5 new 3.5 RC3 installations, disabling sometimes both plugins, sometimes one OR the other, I can say:

plg_system_stats is the responsible for the [error] File does not exist: site/installation, referer: site/installation/index.php but this doesn't make any difference in the loading time.

plg_system_updatenotification doesn't return APACHE error but is the responsible for the 6min20seconds loading time.

I had to disable them directly in the database, because if I try to access /administrator before the site I have the same 6min20seconds of wait.

For intranets your best bet is going to be to turn those off in the database as soon as you get updated or run new installations. I ain't got the slightest clue why the stats plugin is trying to redirect to the install app (that somehow seems like a local config issue at first glance; Joomla only tries redirecting there if you have no configuration.php file AND the directory exists). The update plugin is definitely going to cause headaches if you have no outside connection since the HTTP connector doesn't set a timeout by default.

I just installed RC3 on my laptop here in the pub with NO internet
connection. I had no problem at all. Everything worked perfectly and as
expected.

It doesn't happen when I set enabled to plg_system_stats and plg_system_updatenotification in a 3.5-RC4 site updated from 3.4.8. Just in new installations in same intranet servers. Does it make any sense? Still testing here.

OK I've added in a 20 second timeout to the update call 332a2c0 - so we shouldn't have it running for 6 minutes again.

I'm also really confused by the stats issue though :/ until i can understand what's going on there - it's pretty hard to fix :(

I am closing this at this time. @anabarcellos if you are still having the issue please provide more informmation