# Fabric8 Documentation

### Using captial letters in Karaf container name

Fabric8 does not support using captial letters in the karaf.name property in the etc\system.properties. If you change the value, then only use lower case letters.

#### I cannot start fabric8 on Windows

There is a known issue with Java and Windows when using IP6 capable network. You may see errors such as java.net.SocketException: Permission denied: no further information. To resolve this set the KARAF_OPTS to the following in the bin/setenv.bat file.

KARAF_OPTS="-Djava.net.preferIPv4Stack=true"


For more details see the IP6 Java network guide and this knowledgebase solution.