Failed to start - Aliased is not a valid value for EdgeMode

[Nikola Djurdjevic]

I recently installed Windows 10 from scratch and updated it to the latest version. I also installed the latest version of SourceTree (3.4.30). When I start the application and try to register a user account, I get the following error:

ERROR [2026-03-22 13:52:25,177] [1] [SourceTree.App] [Log] - Failed to start
System.Windows.Markup.XamlParseException: Initialization of 'System.Windows.Setter' threw an exception. ---> System.FormatException: Aliased is not a valid value for EdgeMode.

I have investigated, and it seems to be related to the WPF version installed. However, I already have the latest version. Has anyone had the same experience? Any ideas? The SourceTree just crashes. 

[Tomislav Tobijas]

Hi @Nikola Djurdjevic ,

You could try the following:

• Clear Sourcetree config. > close Sourcetree, navigate to "LocalAppData\Atlassian" and find the folder "Sourcetree.exe_<random_string>" and rename or delete it.
  After that, try restarting Sourcetree.
• Check .NET framework > ensure you have .NET framework 4.8 or higher is fully updated via Windows Update. Potentially, some sub-components of the WPF stack may still be pending updates

I'm on Win 11 (not sure if I have any VM machine with Win 10 to simulate this). 👀

Question - Does the crash happen immediately upon launch, or only when the registration window specifically tries to load? 👀

You could also check Microsoft Edge WebView 2 Runtime - apparently app could rely on Edge components for its registration and login screens, but I'm not sure about the details there. That's only something I managed to dig out. 🤔

Cheers,
Tobi

[Nikola Djurdjevic]

Hi Tobi, 

Thank you for your reply. 

It crashes after Registration window when I click on Next.

I have tried all you have mentioned. I have tried what ChatGPT also suggested. Also I have manually re-installed .NET 4.8.1. All updates are installed. ChatGPT give me a hint that it is related to WPF. 

Below is a little bit bigger log.

ERROR [2026-03-22 20:33:15,492] [1] [SourceTree.App] [Log] - Failed to start
System.Windows.Markup.XamlParseException: Initialization of 'System.Windows.Setter' threw an exception. ---> System.FormatException: Aliased is not a valid value for EdgeMode. ---> System.ArgumentException: Requested value 'Aliased' was not found.
at System.Enum.TryParseEnum(Type enumType, String value, Boolean ignoreCase, EnumResult& parseResult)
at System.Enum.Parse(Type enumType, String value, Boolean ignoreCase)
at System.ComponentModel.EnumConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
--- End of inner exception stack trace ---
at System.ComponentModel.EnumConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
at System.Windows.Setter.System.ComponentModel.ISupportInitialize.EndInit()
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard(XamlType xamlType, Object obj, Boolean begin)
--- End of inner exception stack trace ---
at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
at System.Windows.FrameworkTemplate.LoadTemplateXaml(XamlReader templateReader, XamlObjectWriter currentWriter)
at System.Windows.FrameworkTemplate.LoadTemplateXaml(XamlObjectWriter objectWriter)
at System.Windows.FrameworkTemplate.LoadOptimizedTemplateContent(DependencyObject container, IComponentConnector componentConnector, IStyleConnector styleConnector, List`1 affectedChildren, UncommonField`1 templatedNonFeChildrenField)
at System.Windows.FrameworkTemplate.LoadContent(DependencyObject container, List`1 affectedChildren)
at System.Windows.StyleHelper.ApplyTemplateContent(UncommonField`1 dataField, DependencyObject container, FrameworkElementFactory templateRoot, Int32 lastChildIndex, HybridDictionary childIndexFromChildID, FrameworkTemplate frameworkTemplate)
at System.Windows.FrameworkTemplate.ApplyTemplateContent(UncommonField`1 templateDataField, FrameworkElement container)
at System.Windows.FrameworkElement.ApplyTemplate()
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

[Tomislav Tobijas]

Ah, thanks for the detailed log @Nikola Djurdjevic 🙏

I mean, I'm mainly searching for possible root causes, and this is something that you could potentially check:

...

Potential System Conflict

One known cause for WPF initialization failures in Atlassian tools on Windows is the FIPS (Federal Information Processing Standard) policy. If enabled, it can prevent certain UI components from initializing correctly.

To check and disable this:

1. Go to Start > Control Panel > Administrative Tools > Local Security Policy.

2. Navigate to Local Policies > Security Options.

3. Locate System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing.

4. If it is Enabled, set it to Disabled and restart your machine.

Registry Verification

Ensure the following registry subkey is set to 0:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\fipsalgorithmpolicy.

Since you mentioned this happens specifically after clicking "Next" in the registration window, it is possible the embedded browser component is triggering this. Have you tried temporarily disabling hardware acceleration in your Windows display settings to see if the registration window loads differently?

...

I'm a bit shooting blindly here as I cannot replicate the thing on my machine, but potentially someone else will chime in if they have had a similar experience in the past 🫤