How to Fix WildFly 41 ModuleLoadException: Access Denied on Elytron JAR Files

A common startup issue on Windows systems can prevent WildFly 41 from booting correctly. The server stops during module loading with a ModuleLoadException pointing to one of the Elytron modules.

A typical error message looks like the following:

Exception in thread "main" org.jboss.modules.ModuleLoadException:
Error loading module from
C:\wildfly-41.0.0.Final\modules\system\layers\base\org\wildfly\security\elytron-base\main\module.xml

Caused by: java.io.FileNotFoundException:
wildfly-elytron-x500-cert-2.9.2.Final.jar (Accesso negato)

Symptoms

• WildFly 41 does not start.
• The failure happens very early during boot.
• The stack trace points to an Elytron module.
• The affected JAR file appears to exist in the filesystem.
• The root cause contains Accesso negato or Access denied.

Understanding the Root Cause

At first glance, the exception may suggest that the JAR file is missing:

java.io.FileNotFoundException:
wildfly-elytron-x500-cert-2.9.2.Final.jar

However, the crucial part is:

(Accesso negato)

This means that the file was located successfully, but the JVM could not open it. During startup, WildFly reads every module JAR through the JBoss Modules framework. If Windows blocks access to the file, module loading fails and the server terminates immediately.

In our case, we also noticed that ESET LiveGuard was triggered while WildFly was starting. This is an important clue because endpoint protection products can temporarily lock JAR files while inspecting them, causing WildFly startup to fail.

Common Causes

1. ZIP Extraction Problems

Verify that the file actually exists:

dir C:\wildfly-41.0.0.Final\modules\system\layers\base\org\wildfly\security\elytron-base\main

2. Windows Security Blocking Downloaded Files

Check:

Properties -> General -> Unblock

3. Antivirus or Endpoint Protection

Consider excluding:

C:\wildfly-41.0.0.Final

from real-time scanning.

4. Incorrect NTFS Permissions

icacls C:\wildfly-41.0.0.Final

If needed:

icacls C:\wildfly-41.0.0.Final /grant Users:(RX) /T

5. Running Without Administrative Privileges

In our case, the issue was resolved by starting Windows PowerShell as Administrator before launching WildFly.

cd C:\wildfly-41.0.0.Final\bin
.\standalone.bat

6. Installation Under a Restricted Directory

Avoid:

C:\Program Files
C:\Program Files (x86)

Prefer:

C:\wildfly-41.0.0.Final

Verification

jar tf wildfly-elytron-x500-cert-2.9.2.Final.jar

Start WildFly:

bin\standalone.bat

Successful startup:

WFLYSRV0025: WildFly Full started

Additional Troubleshooting

1. Delete the installation directory.
2. Download a fresh WildFly 41 distribution.
3. Verify the archive checksum.
4. Extract using 7-Zip.
5. Run PowerShell as Administrator.
6. Temporarily disable endpoint protection for testing.
7. Check ESET LiveGuard logs.

Conclusion

When WildFly reports a ModuleLoadException together with a FileNotFoundException containing "Access denied", the JAR file is usually present but inaccessible.

In our case, the solution was simply launching Windows PowerShell as Administrator before starting WildFly 41. Combined with ESET LiveGuard activity during startup, this strongly suggested a permissions or security interception issue rather than a missing module.