ReferenceError: initializeFieldsetDataByDefault is not defined Magento 2.2.2 Upgrade

[Sanjay Jethva]

I have upgraded website from 2.0.7 to Magento 2.2.2 but when i try to open product or category in admin than console showing me below error.

ReferenceError: initializeFieldsetDataByDefault is not defined

Also exception log is showing below error

main.CRITICAL: The element 'gallery' already has a child with alias 'content' {"exception":"[object] (Magento\\Framework\\Exception\\LocalizedException(code: 0): The element 'gallery' already has a child with alias 'content' at /var/www/vhosts/httpdocs/vendor/magento/framework/Data/Structure.php:611)"} []

You can see the screenshot below for admin layout.

https://prnt.sc/iby5fv

Let me know if any one has a solution.

Looking forward to your reply.

[Damian Culotta]

Hi @Sanjay Jethva,

Are you using 3rd-party module that changes or adds features to those modules?

[Damian Culotta]

Let us know how the issue report goes: https://github.com/magento/magento2/issues/13578

[Sanjay Jethva]

Hi @Damian Culotta,

Thanks for your reply.

Actually i didnt get any reply on this error. So i have also report issue in github.

I am using extensions but it want affect product and category edit.

Thanks

[Cypher909 · Accepted solution]

I solved this issue in chrome by opening the inspector, going to the Application tab, and clearing all the site data. Then logged back in and the issue was gone.