[SOLVED] difficulties to log in after upgrade to 1.10

[frankmanl]

I upgraded 9 websites from 1.9.4.3 to 1.10
With two of them I now have difficulties to log in.
After entering login name and password on mywebsite/admin/login.php nothing seems to happen, I stay on that login page.
But when I then remove /login.php from the URL (I found that out by accident) I'm suddenly in the backend of the site and everything works fine.
What causes this behaviour? How can I solve it?

Frank

[ruil22]

I had the same problem with one of may website.

I fixed it so:
I login without /login.php, go to User Preferences, I changed settings and everything is OK now!

Excuse me for my bad English!

[frankmanl]

I just found out that for some websites the admin has no troubles, but editors do.
For at least one site all users have this problem.

[frankmanl]

Thanks Ruil22, That helps me.
Indeed, all accounts that had this problem had this setting:
My Preferences » User Preferences » Homepage: None
Changing that to i.e. Homepage: Content solved this problem.