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What “Mrm resource type mismatch” means
Windows uses the Modern Resource Manager (MRM) to select packaged resources such as localized strings, images, and other assets. Error 15117, ERROR_MRM_RESOURCE_TYPE_MISMATCH, is defined as Invalid ResourceCandidate type.
A resource candidate is an item in a package’s resource data that MRM may choose for the current language, scale, device configuration, or other context. The error occurs when the candidate’s type does not match the type MRM expects.
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MrmCoreR.dll is an associated Windows runtime component. Seeing that filename does not mean the DLL itself should be downloaded, replaced, registered, or removed. The failing object is usually a packaged resource or the package metadata that describes it.
The definition identifies the immediate failure, but it does not name one universal cause. In practice, the package may contain malformed or stale generated resource data, an incorrect declaration, or output produced with incompatible build tooling. Those are cause categories to investigate, not a guaranteed diagnosis for every occurrence.
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First determine who needs to act
The correct repair depends on whether you are running one affected app or building the package yourself. Capture the context before changing anything:
- Copy the complete error text and record both decimal 15117 and hexadecimal
0x3B0Dif they appear. - Note the application name, publisher, package identity (if shown), Windows edition and build, and the exact action that triggered the message.
- Check whether the failure is limited to one app or occurs in several unrelated packaged apps.
- Record whether the app came from the Microsoft Store, an enterprise deployment, a vendor installer, or a development build.
A single failing app points first to that package, its generated resources, or its local cache. Several unrelated apps shift attention toward Windows servicing and system integrity. If you are the app developer or packager, use the build and packaging procedure rather than repeatedly resetting the installed app.
Fix one affected app as an end user
1. Close the app and retry once
Exit the app and any related background process, then start it again and repeat the action that produced the error. If the message was a one-time failure during an update or first launch, this distinguishes a transient interruption from a repeatable package problem. If it returns, continue with the repair steps below.
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- Open Settings.
- Go to Apps > Installed apps (Windows 11) or Apps & features (Windows 10).
- Select the affected app, open its Advanced options, and choose Repair when that option is available.
- Launch the app and test the same operation.
Repair is the least disruptive option because it attempts to correct the installation without intentionally removing the app’s stored data. The exact buttons vary by app type and Windows build; a packaged app may expose Repair while a traditional desktop installer may not.
3. Reset the app if Repair fails
- Return to the app’s Advanced options page.
- Select Reset and confirm.
- Open the app, sign in again if required, and test the failing feature.
Reset can remove the app’s local settings, cached data, and sign-in state. Back up or synchronize any data the app stores only on this PC before using it. If the error disappears after Reset, the previous local package or resource cache was a plausible contributor; the error definition alone cannot prove which file was damaged.
4. Update the app and Windows
Install updates from the same trusted source that supplied the app. For a Microsoft Store app, open the Store, choose Library, and select Get updates. For an organization-managed app, use the organization’s software portal or ask its administrator. Also open Settings > Windows Update and install pending updates, restarting when Windows requests it. A newer package can replace invalid generated resources, while Windows updates can address servicing components used by packaged apps.
5. Reinstall from the original trusted source
If Repair, Reset, and updating do not help, uninstall the affected app, restart Windows, and reinstall it from the original trusted source. Avoid third-party DLL download sites and unofficial repackaged installers. Reinstallation creates a fresh package and resource set, but it may remove local data or require you to configure the app again, so export important settings first when the app provides that feature.
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If the same error returns immediately after a clean reinstall while other apps work normally, preserve the exact message, package identity, and Windows build and contact the app vendor or your administrator. That pattern is more useful to the package maintainer than repeatedly deleting system files.
When several unrelated apps show the error
Multiple failures suggest a Windows servicing or system-integrity problem rather than one corrupt app package. Work from least disruptive to most disruptive:
1. Install pending Windows updates
Go to Settings > Windows Update, select Check for updates, install everything offered for your edition, and restart. Test more than one previously failing app after the restart.
2. Run the built-in system integrity checks
Open Windows Terminal (Admin) or Command Prompt (Admin). Run the servicing check first, wait for it to finish, and then run System File Checker:
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsDISM.exe /Online /Cleanup-Image /RestoreHealth
sfc /scannowRestart after both commands complete and retest the affected apps. These checks are appropriate when Windows components may be damaged; they do not repair a malformed resource declaration inside a particular third-party package. If either command reports that it could not complete, record the message rather than repeatedly interrupting it.
3. Use an in-place Windows repair when integrity checks do not resolve it
An in-place repair installation refreshes Windows while normally preserving personal files and installed applications, but the available procedure depends on the Windows edition and build. Back up important data, disconnect unnecessary external devices, and use installation media or an official Windows setup path that matches the installed edition and language. Choose the option to keep personal files and apps when it is offered. If that option is unavailable, stop and verify the edition and media before proceeding; a clean installation has substantially greater data and application impact.
Developer and packager workflow
If you maintain the app that produces the error, repairing the installed copy only hides the underlying packaging defect. Reproduce the failure with the exact package identity, architecture, configuration, Windows build, and action that triggers it, then inspect the newly generated resources.
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1. Clean generated output
Remove the build output and intermediate generated-resource directories using your normal build-system procedure. Regenerate the resource files and PRI artifacts from the source declarations instead of reusing files from an earlier build, branch, architecture, or configuration. Keep the old package available for comparison, but do not mix its generated resource output into the new package.
2. Verify every resource declaration and candidate type
Review the declarations for strings, images, scale variants, language qualifiers, and other packaged assets. Confirm that each declaration produces the candidate type expected by the consuming API and that a file was not declared as one resource kind while being emitted as another. Look for stale entries left after a rename, an asset copied from a different project, or metadata generated by a tool version that does not match the rest of the build.
3. Check architecture and configuration consistency
Make sure the package manifest, generated resources, referenced libraries, and build configuration target the same architecture and intended configuration. A resource generated for one variant must not be silently reused for another. Repeat the check for language and scale qualifiers: an incorrectly qualified candidate can make the package appear valid in one environment and fail when MRM selects a different candidate.
4. Align the Windows SDK and toolchain
Rebuild with a Windows SDK and packaging toolchain compatible with the target operating-system versions. Do not combine resource-generation tools from unrelated SDK installations unless your build documentation explicitly supports that combination. Record the SDK, compiler, packaging-tool versions, target architecture, and Windows build in the failing and corrected builds so the result is reproducible.
5. Test the fresh package on a clean environment
Install the newly built package on a clean test machine or clean virtual environment that does not contain the previous package’s generated cache. Exercise every resource path associated with the failure, including the language, scale, and configuration that originally reproduced it. If the clean package works but an upgrade fails, test the upgrade path separately; stale package state may be involved even when a first install succeeds.
Choosing the next remedy
| Observed pattern | Most likely area to investigate | First action | Impact and reversibility |
|---|---|---|---|
| One app fails; other apps work | Affected package, generated resources, or local app cache | Repair, then Reset, update, and reinstall | Repair is low impact; Reset and reinstall can remove local data |
| Several unrelated apps fail | Windows servicing or system integrity | Install updates, run DISM and SFC, then consider in-place repair | Updates and integrity checks are normally reversible; in-place repair needs a backup and matching media |
| Failure appears only in a development or newly packaged build | Resource declarations, candidate types, generated PRI output, or toolchain mismatch | Clean generated output and rebuild with aligned SDK/tool versions | Requires a new package; does not modify the user’s installed app until deployed |
| Fresh package fails on a clean machine | Package contents or declarations | Inspect the resource manifest and candidate type mapping | Fix belongs in source and packaging configuration |
| Fresh package works, upgrade fails | Upgrade state or stale installed-resource data | Reproduce the upgrade path and test uninstall/reinstall as a diagnostic | Uninstall/reinstall can remove local data; preserve logs and package identities |
What not to do
- Do not delete, rename, download, or replace
MrmCoreR.dllfrom an unofficial source. - Do not register the DLL with
regsvr32; this error concerns a resource candidate type, not a missing registration step. - Do not assume a generic driver update will correct a package-resource mismatch. The failing object is normally app metadata or generated resource output.
- Do not repeatedly reset an app when several unrelated apps fail; change the investigation to Windows servicing and integrity.
- Do not publish a rebuilt package without testing it on a clean environment and through the upgrade path that failed.
Information to include when escalating
Give the vendor, administrator, or internal build team enough detail to reproduce the selection of the invalid candidate:
- Complete error text, decimal code 15117, and hexadecimal
0x3B0D. - Application name, package identity, version, architecture, and installation source.
- Windows edition and build, language, and the action that triggers the error.
- Whether Repair, Reset, update, reinstall, DISM, and SFC changed the behavior.
- For developers: the SDK and packaging-tool versions, build configuration, generated PRI/resource artifacts, and whether a clean-machine test passes.
This information separates an app-specific packaging defect from a system-wide servicing issue and prevents unsupported fixes such as replacing a Windows DLL.
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