I cannot reset my Security Token in Sandbox Org. The "Reset My Security Token" button in the My Settings, Personal tab doesn't appear. Any idea?
From Knowledge Article Common Questions about Security Tokens: https://help.salesforce.com/HTViewSolution?id=000003783
Q: When I go to Setup | My Personal Information, I do not see Reset My Security Token. Why?
A: There are a few reasons why this option is not available in the navigation pane. Note this would also cause a security token to NOT be received via email upon reset of the user's password:
- SSO (Single Sign On) is enabled for the org: If SSO is enabled, security tokens are not used, so it would not be available as an option.
- IP Restrictions are enabled for the Profile: This also would result in the disablement of the Security Token.
- The User's Profile is corrupted: If neither of the above options are true/apply, try editing the profile and then saving it without making any changes at all. This will "reset" the profile, and might result in the token option being available.
- ID confirmation may have been disabled or if re-enabled a permission was not set correctly. Please have salesforce.com customer support ensure that the appropriate permissions are active on your Org. For more in depth information about Reset My Security Token, please review this link.
Here is the workaround:
When you have trusted IP ranges enabled, you won't see the reset token link if you're logged in from an address in a trusted range. To get around this, we use the below URL:
Just make sure that you're logged in as the user you want to reset. This URL has been a lifesaver for us.
taken from here