This article will explain the root cause and solution to resolve the below exception while running 'kinit' command :
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kinit.bat -k -t <spotfire_Server_Install_dir>\tomcat\spotfire-config\Spotfire.keytab HTTP/test_tssserver.demo.com@demo.com

Exception: krb_error 41 Message stream modified (41) Message stream modified 
KrbException: Message stream modified (41) 
        at sun.security.krb5.KrbKdcRep.check(KrbKdcRep.java:45) 
        at sun.security.krb5.KrbAsRep.decrypt(KrbAsRep.java:158) 
        at sun.security.krb5.KrbAsRep.decryptUsingKeyTab(KrbAsRep.java:121) 
        at sun.security.krb5.KrbAsReqBuilder.resolve(KrbAsReqBuilder.java:285) 
        at sun.security.krb5.KrbAsReqBuilder.action(KrbAsReqBuilder.java:361) 
        at sun.security.krb5.internal.tools.Kinit.<init>(Kinit.java:219) 
        at sun.security.krb5.internal.tools.Kinit.main(Kinit.java:113) 
----------------- 

Cause: 
You may come across this exception when you run above 'kinit' command with realm in lower case(for example: @demo.com).
 

"Exception: krb_error 41 Message stream modified (41) message stream modified" while running 'kinit' command during Spotfire server Kerberos setup.

All Supported OS

There are two things that need to check:

A)

- Check whether the keytab file that you have generated (using ktpass command) earlier has the realm in lower case. If yes, you need to run ktpass command again to create keytab file with realm in upper case and use this newly created keytab file in rest of kerberos configuration.

Refer below manual for more information related to ktpass command and realm part in command: 
https://docs.tibco.com/pub/spotfire_server/10.3.8/doc/html/TIB_sfire_server_tsas_admin_help/GUID-48920907-A433-4383-9637-52457D05C68A.html

- After creating new keytab file in above step, run kinit command with realm in upper case as below:
--------- 
kinit.bat -k -t <spotfire_Server_Install_dir>\tomcat\spotfire-config\Spotfire.keytab HTTP/test_tssserver.demo.com@DEMO.COM
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B)

- If the keytab file that you have generated (using ktpass command) earlier has the realm in upper case then you only need to run kinit command with realm in upper case as below:
--------- 
kinit.bat -k -t <spotfire_Server_Install_dir>\tomcat\spotfire-config\Spotfire.keytab HTTP/test_tssserver.demo.com@DEMO.COM
----------

Refer below manual for more information related to ktpass command and realm part in command: 
https://docs.tibco.com/pub/spotfire_server/10.3.8/doc/html/TIB_sfire_server_tsas_admin_help/GUID-48920907-A433-4383-9637-52457D05C68A.html