Oracle Fusion Middleware: OBIEE BootIdentity Error - Boot.properties - Boot Identity Hatası

BootIdentity error was something that we have encountered before but we havent document it before.
We can encounter with this problem in either bi_server.log or admin server logs. (e.g. E:\oracle\obia\user_projects\domains\obia_domain\servers\AdminServer\logs or E:\oracle\obia\user_projects\domains\obia_domain\servers\bi_server\logs)

Basically the error could look like the text below


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[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'Authentication denied: Boot identity not valid; The user name and/or password from the boot identity file (boot.properties) is not valid. The boot identity may have been changed since the boot identity file was created. Please edit and update the boot identity file with the proper values of username and password. The first time the updated boot identity file is used to start the server, these new values are encrypted.
Server subsystem failed. Reason: weblogic.security.SecurityInitializationException: Authentication denied: Boot identity not valid; The user name and/or password from the boot identity file (boot.properties) is not valid. The boot identity may have been changed since the boot identity file was created. Please edit and update the boot identity file with the proper values of username and password. The first time the updated boot identity file is used to start the server, these new values are encrypted.
weblogic.security.SecurityInitializationException: Authentication denied: Boot identity not valid; The user name and/or password from the boot identity file (boot.properties) is not valid. The boot identity may have been changed since the boot identity file was created. Please edit and update the boot identity file with the proper values of username and password. The first time the updated boot identity file is used to start the server, these new values are encrypted.
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This can be commonly seen in the Fusion Middleware environments as boot.properties file gets corrupted.

Solution:
To solve this problem we backup the old boot.properties file for each server which is found in their corresponding security folders.
(e.g E:\oracle\obia\user_projects\domains\obia_domain\servers\bi_server1\security)
After the  backup, we delete boot.properties file and start the weblogic or bi_server1(or any managed weblogic server). When we start that server we will be asked to enter username and password and that is how we fix and update the corrupted username and password. In the end we will be able to start the server.