Troubleshooting
Problem
When running applications on .NET 5, .NET Core 3.1, or older versions with Instana Tracing Core v1.315.5 or later, the profiler fails to load and instrumentation is not applied to the application.
Cause
The default .NET 5 container images are based on Debian Buster, which includes an outdated version of libstdc++. This outdated library lacks the required GLIBCXX symbols that the Instana profiler depends on, preventing the profiler from loading correctly.
Base images for Instana profiler has been recently updated and will no longer work with applications on .NET 5, .NET Core 3.1, and older, resulting in instrumentation not being applied.
Environment
Affected versions:
.NET / .NET Core Tracer 1.315.5 and later
Resolving The Problem
Workaround Steps:
- Update your Dockerfile or container configuration to use the Bullseye-based image
- Replace any references to the default .NET 5 image with mcr.microsoft.com/dotnet/sdk:5.0-bullseye-slim
- Rebuild your container image
- Redeploy your application with the updated container image
- Verify that the Instana profiler loads successfully and instrumentation is applied
Note: This issue specifically affects Instana Tracing Core v1.315.5 and later versions when used with .NET 5, .NET Core 3.1, and older versions. The Bullseye-based images include the required libstdc++ version with the necessary GLIBCXX symbols.
If this workaround does not restore instrumentation, please reach out to Instana Support via a case so we can review and assist.
Related Information
[Supported Runtimes](https://www.ibm.com/docs/en/instana-observability/1.0.315?topic=technologies-monitoring-net-net-core#ariaid-title5)
[Supported libraries and frameworks for tracing](https://www.ibm.com/docs/en/instana-observability/1.0.315?topic=technologies-monitoring-net-net-core#ariaid-title6)
Document Location
Worldwide
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Document Information
Modified date:
15 April 2026
UID
ibm17269576