Steps to recreate the issue:

1. Launch the SnowSoftware.Update.Gui application.
2. This will lead to no action.
3. Reviewing the Event Viewer application logs we get the following error:

Navigate to c:\program files\snow software\snow update service\ and run the snowsoftware.update.gui.exe.  If this doesn't work successfully:

• Take a copy of the folder: C:\Program Files\Snow Software\Snow Update Service
• Please run the below Powershell commands in Powershell ISE (this must be run as an Administrator):

# Path To SUS installation
$SUSPATH = "C:\Program Files\Snow Software\Snow Update Service"

# Download files from Portal 
Invoke-WebRequest -Uri https://updatesportal.snowsoftware.com/download/sus -OutFile C:\Temp\SUS_Latest.zip

# Stop Service
Stop-Service -Name "SnowUpdateService" -Verbose -ErrorAction Continue

# Close Down Gui 
Get-Process -Name SnowSoftware.Update.Gui | Stop-Process -ErrorAction Continue

# Close Down Update Background Service
Get-Process -Name SnowSoftware.Update.Service | Stop-Process -ErrorAction Continue

# Close Down Tray Notification Service
Get-Process -Name SnowSoftware.Update.TrayNotification | Stop-Process -ErrorAction Continue

# Close down SRS client 
Get-Process -Name srsc | Stop-Process -ErrorAction Continue

# Delete content of SUS, saving History
Get-ChildItem $SUSPATH -Exclude "Resources","UpdateHistory.xml" -Force | Remove-Item -Recurse -Force -Confirm:$false

# Unpack files
Expand-Archive -Path c:\temp\SUS_Latest.zip -DestinationPath $SUSPATH -Force

# Start Service
Start-Service "SnowUpdateService" -Verbose

If after completing these steps you are experiencing an issue where update history is showing wrong product version please see our knowledge article for further advice.