"Network Topology Mapper can't open this map" Error when opening the Maps after Upgrading to NTM 2.4

Network Topology Mapper version 2.4 requires a specific upgrade path due to the database changes on this version.
As per NTM 2.4 release notes :

NTM 2.4 changes the database used to store 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 upgrading from a version earlier than NTM 2.3., upgrade to NTM 2.3 first and then upgrade to NTM 2.4.

If not followed correctly, you might get the following error message when accessing the map in the latest version:

Network Topology Mapper can't open this map.

• Failure to migrate the NTM database map from Microsoft SQL Server Compact Edition to SQLite.

• Prior to Upgrading your NTM to version 2.4, ensure that all maps used are stored in: C:\ProgramData\SolarWinds\Network Topology Mapper\UserMap 
• As per the Release Note: 

  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.

Revert the Server to a snapshot prior to the upgrade then retry the whole upgrade process and ensure that all maps are saved in C:\ProgramData\SolarWinds\Network Topology Mapper\UserMaps.

Saving it on the said location after the upgrade will not migrate the Maps from Microsoft SQL Server Compact Edition Database to SQLite Database of NTM 2.4.

If maps are already saved in the said location but still getting this issue, a possible error during the upgrade process might occur.
Revert to snapshot and retry the upgrade.