App crashes with SIGSEGV in FileEncryptionManager.createMAMIdentity when no App Protection Policy is configured

[nakajijapan]

Questions to Ask Before Submission

1. Have you completed the exit criteria for each phase in the Intune App SDK for Android Integration Guide?
   Yes

2. Have you checked the Microsoft Intune App SDK for Android repository for similar issues?
   Yes - Found Issue Crash occurring when using Intune with Realm Java SDK #253 which has a similar crash pattern but different root cause (Realm SDK)

3. Are you using the latest version of the SDK?
   Yes

Summary

App crashes immediately on startup with a NullPointerException followed by SIGSEGV when:

• MAM SDK is integrated
• Company Portal is installed
• No App Protection Policy is assigned to the user

The crash occurs in the "Verification th" background thread during SDK initialization, specifically in FileEncryptionManager.createMAMIdentity.

Repro Steps

1. Integrate MAM SDK 12.0.3 into a Flutter Android app using the Gradle Build Plugin
2. Build release APK and distribute via Intune as a private/LOB app
3. Install on a device with Company Portal installed (user has NO App Protection Policy assigned)
4. Launch the app

Expectation:
App launches normally without crashes

Observation:
App crashes immediately with SIGSEGV

Stack Trace

W System.err: java.lang.NullPointerException: Attempt to read from field 'java.lang.ThreadLocal$ThreadLocalMap java.lang.Thread.threadLocals' on a null object reference in method 'java.lang.ThreadLocal$ThreadLocalMap java.lang.ThreadLocal.getMap(java.lang.Thread)'
W System.err:   at com.microsoft.intune.mam.log.MAMLogger.enabled(:449)
W System.err:   at com.microsoft.intune.mam.log.MAMLogDisabler.<init>(:21)
W System.err:   at com.microsoft.intune.mam.client.fileencryption.FileEncryptionManager.createMAMIdentity(:697)
F libc    : Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0 in tid (Verification th)

Native crash details:

F DEBUG   : esr: 0000000092000006 (Data Abort Exception 0x24)
F DEBUG   :   NOTE:   /data/user/.../mam_libs/arm64-v8a/libmsmdmarp.so
F DEBUG   :       #03 pc 0000000000390484  .../com.microsoft.windowsintune.companyportal-.../base.apk (com.microsoft.intune.mam.log.MAMLogger.createLogRecord+4)

Details

• Intune Android App SDK Version: 12.0.3 (also tested with 11.5.1 - same issue)
• Android Device OS Version: 15
• Company Portal Version: Latest (from Play Store)
• Android Studio Version: Latest
• Framework: Flutter 3.x
• Build Type: Release (with R8/ProGuard enabled)
• App Protection Policy: None configured

Additional Context

• The crash happens in a background thread named "Verification th"
• Native libraries are loaded from Company Portal: libmsmdmarp.so, libmsmam-pre.so, libwolfssl.so, liborigin.so
• MAMInfo log shows: MAMInfo initialized. Debug=false, Agent=PRODUCTION, ManagedDialogDisabled=false, PolicyRequired=false
• The crash is 100% reproducible when no App Protection Policy is assigned

Workaround Attempted

• Tried SDK versions 12.0.3 and 11.5.1 - same crash
• Added comprehensive ProGuard keep rules for MAM SDK classes - no effect
• Cleared app data and reinstalled - no effect
• Updated Company Portal to latest - no effect

Expected Behavior

The SDK should gracefully handle the case where no App Protection Policy is configured, rather than crashing during initialization.

[nakajijapan]

Update: Root Cause Identified - Android 16 (API 36) Compatibility Issue

After further investigation, the root cause has been identified: this is an Android 16 (API 36) compatibility issue, not an SDK configuration problem.

Device Information (Correction)

• Build fingerprint: google/tokay/tokay:16/BP4A.260105.004.E1/14587043:user/release-keys
• Actual Android Version: Android 16 (API 36) Developer Preview/Beta
• Device: Pixel 9 (tokay)

Root Cause Analysis

The crash occurs in BackgroundVerificationTask (an ART runtime background verification thread):

#00 pc java.util.logging.LogRecord.defaultThreadID+44
#03 pc com.microsoft.intune.mam.log.MAMLogger.createLogRecord+4

MAMLogger is called from BackgroundVerificationTask, which triggers LogRecord.defaultThreadID(). This method calls Thread.currentThread() on a thread that is not properly initialized in Android 16's ART runtime.

SDK Version Testing

Tested multiple SDK versions - all crash at the same location:

• SDK 11.5.1 → Crash
• SDK 12.0.3 → Crash

Conclusion

This is an Android 16 compatibility issue. The SDK does not currently support Android 16 (API 36), which is still in Developer Preview/Beta.

Temporary Workaround

• Use Android 14 or Android 15 devices for testing
• Wait for Android 16 official release and SDK update

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Please let us know if Android 16 support is planned and an estimated timeline for compatibility updates.