When you want to install specific software from http://downloads.cc.dtu.dk the local username of your machine must match your DTU login.

If you need to change your account name in Windows 7/8/10 follow the instructions below:

Windows 7

1. Click "Start" button and then "Control Panel"
2. Click "User Accounts and Management Safety" and then "User Accounts"
3. Click "Change your Account Name". Type your new computer name and click "Change Name"

Alternatively, visit Microsoft homepage

Windows 8

1. Click "Start" button and then "Control Panel"
2. Click to open Control Panel’s "User Accounts and Family Safety category"
3. Click "User Accounts" link and then click "Change the account name".

Alternatively, visit Microsoft homepage

Windows 10

1. Press Windows+X and select Control Panel.
2. Select User Accounts
3. Under Make changes to user account, click on "Change your account name"

If you have logged on using a Microsoft (Hotmail or outlook) account then the above does not work and you would need to change your Microsoft account. Instead you can run:

1. Windows+R, enter lusrmgr.msc
2. Open Users from left menu
3. Right mouse click on your account and select Rename

Alternatively you can create a new local account and run the applications using the "runas" command.
To run Comsol on Windows 10 as a user that matches your DTU student ID:

Create a Windows shortcut with the following Target (all one line):

C:\Windows\System32\runas.exe /user:sxxxxxx /savecred 
"C:\Program Files\COMSOL\COMSOL52\Multiphysics\bin\win64\comsol.exe"

In all cases logout and in again for the changes to take effect. To check the Windows user name run the following in a Windows Command prompt:

echo %USERNAME%