| Feature | VSTO 2010 Runtime | VSTO 2015+ Runtime (part of Office) | |---------|-------------------|--------------------------------------| | Included in Office | No | Yes (Office 2013 SP1+) | | Supports .NET 4.8 | Yes | Yes | | Supports Office 2019 | No | Yes | | ClickOnce updates | Yes | Yes (improved) | | Standalone redistributable | Yes | No – bundled with Office |
It creates isolated application domains for each solution assembly to ensure stability and prevent conflicts between different add-ins.
The specific version—the —was a major turning point. Before 2010, VSTO runtimes were tied to specific versions of Visual Studio. If a user installed an app built in VS2008 and another built in VS2005, they often broke each other. visual studio 2010 tools for office runtime
Windows 7 SP1 through ; Windows Server 2012–2019 Framework .NET Framework 3.5 , 4.0 , or later must be installed first Office Version Microsoft Office 2013 , 2016, or newer supported versions Architecture
Visual Studio Tools for Office runtime overview - Microsoft Learn | Feature | VSTO 2010 Runtime | VSTO
For teams maintaining existing VSTO 2010 solutions, the runtime remains functional on Windows 10/11 with Office 2013–2016, but careful testing and security isolation are advised.
Microsoft strongly recommends migrating to or VSTO 2019 runtime (if desktop add-ins are required) for Office 2016+. If a user installed an app built in
| Issue | Typical Cause | Workaround | |-------|---------------|-------------| | "Cannot load add-in" | Missing VSTO runtime or wrong .NET Framework version | Install vstor_redist.exe and target .NET 4.0+ | | "The add-in is not signed" | Deployment manifest lacks Authenticode signature | Sign with a valid code-signing cert | | "Office crashes on load" | Native shim conflict with antivirus | Add shim and add-in assembly to AV exclusion list | | "64-bit Office cannot load add-in" | Add-in compiled for AnyCPU but relies on 32-bit COM | Recompile for x64 or use 32-bit Office |