Why am I getting “Store is a namespace” or similar compile errors after upgrading to Unity IAP 5.x?

• CS0118: “‘Store’ is a namespace but is used like a type”
• CS0104: “‘Product’ is an ambiguous reference”
• CS0433: “Type ‘X’ exists in both ‘AssemblyA’ and ‘AssemblyB’”

• Unity IAP 5.x introduces or expands public types that use short, generic names (such as the Store enum or the Product class).
• If your code or a third-party plugin exposes the exact same names at the global root of your project, the compiler may resolve your symbols where the IAP package expects its own.
• Assembly Definition files (.asmdef) with the “Root Namespace” set to a generic value like “Store” implicitly create that namespace across the entire assembly. This can trigger collisions even if no individual .cs source file explicitly declares it.

• Use your IDE (Visual Studio, Rider, etc.) to perform a Global Search (Find in Files). Important: Ensure your search scope is set to "Entire Solution" so you do not miss downloaded assets or third-party plugins.
• Search for:
  • namespace Store
  • Types or namespaces named Product, AppleAppStore, or other names mentioned in the compile error.
• Inspect your .asmdef files and verify the “Root Namespace” is not set to “Store” or other generic names.
• Look at the very first compile error in the Unity Console; it typically names the exact symbol that is colliding.

Note: Do not rely on simple C# Reflection scripts (like Assembly.GetExecutingAssembly()) to find these, as they will only scan the specific assembly they are attached to and will miss third-party code.

How to fix

• Rename generic namespaces and types to project-specific names (for example, include your company or game prefix: MyGameStore or InventoryProduct) so they don’t collide with IAP.
• Set distinctive “Root Namespace” values in your .asmdef files.
• If a third-party plugin is the source, update it, configure it to use a unique namespace, or scope its Assembly Definition appropriately (for example, exclude it from player builds if it is an Editor-only tool).
• Where practical in your own code, reference IAP types using their fully qualified namespace (e.g., UnityEngine.Purchasing.Product) to avoid ambiguity.

Notes

• Deleting the Library folder or reimporting assets will not resolve name collisions; you must change the conflicting names or namespaces in the code.
• If you temporarily downgraded IAP to an earlier version to continue development, you should still address the naming conflict before returning to IAP 5.x.

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