Application Error After Upgrading to NTM 2.4

To install NTM version 2.4, you need to follow a certain upgrade path due to its Database upgrade:
2.2 > 2.3 > 2.4

NTM 2.4 changes the database used to store your maps. Changing the supported database requires migrating existing maps from Microsoft SQL Server Compact Edition to SQLite.

Direct upgrades to NTM 2.4 are only supported from NTM 2.3. If you are upgrading from a version earlier than NTM 2.3., upgrade to NTM 2.3 first, and then upgrade to NTM 2.4.

Only maps stored in the default location (C:\ProgramData\SolarWinds\Network Topology Mapper\UserMaps) will be migrated automatically during the upgrade. Maps stored outside of this folder are not migrated and cannot be opened in NTM after the upgrade.

The maps migration runs as a part of the upgrade. If you have a large number of maps or large maps in NTM, the upgrade might take some time. Plan the upgrade accordingly.

Ref: NTM 2.4 release notes 

This article is intended for NTM version 2.4 only.
For NTM 2.2 and NTM 2.3, look for similar articles with the same error message:

NTM 2.2 error Network Topology Mapper encountered an unexpected error and needs to close

NTM 2.3 Application Error When Running a New Network Discovery

• Failure during Database upgrade
• Missing Windows System Requirements

1. Ensure NTM is running as an Admin.
2. Ensure no other SolarWinds Product is installed in the Server that uses "SolarWinds Job Engine" and "Provides Discovery Services for SolarWinds Applications."
3. Follow the Upgrade path: Version 2.2 > 2.3 > 2.4
   • Ref: NTM 2.4 release notes (See Before you Upgrade)
4. Follow System Requirements: NTM 2.4 system requirements 
5. Ensure the version installed is NTM 2.4.0.60020.