Last updated: 01/02/2021


Project administrators have the ability to supplement the wide range of information automatically collected in MigrationStudio by attaching additional files to Application, Migration User and Machine records.  For example, an administrator might want to attach a license file to a particular application or upload a UAT sign-off form.

If the configuration or environment has changed, users may encounter the error 'Handler not found or execution of the handler failed' when attempting to upload attachments:

This Solution Article discusses the steps that an administrator should take to diagnose and resolve the issue.


The solution may require changes to the MigrationStudio configuration and permissions of the server's filesystem.  A MigrationStudio and Windows account with administrator privileges will also be required.

Please note, this Solution Article contains links within the body text that are provided for illustrative purposes only and are not intended to resolve.

Check the Internet Explorer Address

The process that uploads attachments to MigrationStudio relies on the address entered in the Internet Explorer address bar matching the internal server configuration (known as the Site Address) specified in MigrationStudio.  

For example, the image below shows Internet Explorer using the address http://LocalHost/MigrationStudio, which is different from Site Address.  This could cause the 'Handler not found...' error.

Instead, the Site Address http://SVR-MS-001.local/MigrationStudio should be entered in the Internet Explorer address bar.

To retrieve the Site Address used in MigrationStudio:

  • Log into MigrationStudio with an account with administrator privileges.
  • Switch to the Admin view (1) and select Initial Setup (2) from the vertical menu on the left.
  • Make a note of the URL specified in Site Address (3) under Critical Settings.
  • If the address entered in the Internet Explorer address bar (4) does not match the site address, replace it with the URL specified in Site Address.

Using Short DNS Names

MigrationStudio might also generate the 'Handler not found...' error message if the MigrationStudio client (running in Internet Explorer) can't resolve the MigrationStudio server's DNS name. This typically tends to happen when a short DNS name is specified in the MigrationStudio configuration. Replacing the short DNS name with a long, or fully qualified domain name (FQDN), will often resolve the issue.

For example, MigrationStudio is running in the LOCAL domain yet is configured to use http://svr-ms-001/MigrationStudio instead of http://svr-ms-001.local/MigrationStudio (note the additional .local in Site Address).  

Although this configuration will work for many MigrationStudio features, the Site Address should be replaced with the FQDN of the server (http://SVR-MS-001.local/MigrationStudio in this example).

Update the MigrationStudio Site Address Configuration

To update the Site Address configuration with the server's FQDN:

  • Log into MigrationStudio with an account with administrator privileges.
  • Switch to the Admin view (1) and select Initial Setup (2) from the vertical menu on the left.
  • In the Critical Settings panel, enter the FQDN of the MigrationStudio server in Site Address (3). For an internal installation, Site Address should be in the format: 


  • Click the Save Changes button (3) to commit the changes

Reload MigrationStudio using the new FQDN-based site address in the Internet Explorer address bar and attempt to upload an attachment.

Service Account Permissions

If the Service Account used by MigrationStudio doesn't have sufficient permissions on the server's upload folder, MigrationStudio won't be able to upload the attachments.

To view the location of the Upload Folder in MigrationStudio:

  • Switch to Admin (1)
  • Select Initial Setup (2) from the vertical menu on the left
  • Make a note of the Upload Folder path (3)

  • Using a Windows account with administrator privileges, open Windows Explorer and navigate to the Upload Folder path
  • Ensure that the account running the IIS web service has "Modify" rights to the folder
    • Most installations will use an Active Directory Service Account, provided to MigrationStudio prior to installation (create a new Service Desk Ticket if the account details aren't available)
    • Installations based on SQL-authentication, typically PoCs, will use IIS_IUSRS

Further Support

If you require further support, please visit MigrationStudio's Service Desk at to search the knowledge base or create a new support ticket.