I asked the SQL manager to change the collation for the FBA database to Finnish_Swedish_CI_A_S, but it didn't help
The log contains only 3 lines about this
Name=Request (GET:http://customersite:80/sites/mainsite/_layouts/FBA/Management/UserEdit.aspx?UserName=%C3%A5%C3%A4%C3%B6%C3%85%C3%84%C3%96%C3%BC%C3%9C&Source;=http%3A%2F%2Fcustomer%2Fsites%2mainsite%2F%5Flayouts%2FFBA%2FManagement%2FUsersDisp%2Easpx)
Site=/sites/mainsite
Leaving Monitored Scope (Request (GET:http://customersite:80/sites/mainsite/_layouts/FBA/Management/UserEdit.aspx?UserName=%C3%A5%C3%A4%C3%B6%C3%85%C3%84%C3%96%C3%BC%C3%9C&Source;=http%3A%2F%2customersite%2Fsites%2Fmainsite%2F%5Flayouts%2FFBA%2FManagement%2FUsersDisp%2Easpx)). Execution Time=81.374308745944
The log contains only 3 lines about this
Name=Request (GET:http://customersite:80/sites/mainsite/_layouts/FBA/Management/UserEdit.aspx?UserName=%C3%A5%C3%A4%C3%B6%C3%85%C3%84%C3%96%C3%BC%C3%9C&Source;=http%3A%2F%2Fcustomer%2Fsites%2mainsite%2F%5Flayouts%2FFBA%2FManagement%2FUsersDisp%2Easpx)
Site=/sites/mainsite
Leaving Monitored Scope (Request (GET:http://customersite:80/sites/mainsite/_layouts/FBA/Management/UserEdit.aspx?UserName=%C3%A5%C3%A4%C3%B6%C3%85%C3%84%C3%96%C3%BC%C3%9C&Source;=http%3A%2F%2customersite%2Fsites%2Fmainsite%2F%5Flayouts%2FFBA%2FManagement%2FUsersDisp%2Easpx)). Execution Time=81.374308745944