Error when trying to add a product on Magento 2.4.2 after Migration from 1.9

[Vivekv2v]

This is the error message I receive after I press the Add Product button.

Class Magento\Catalog\Model\Product\Attribute\Backend\Price does not exist

[Vivekv2v]

Add new Product

[smita_kagwade]

Hello @Vivekv2v ,

Try giving permissions to your root directory

sudo chown www-data:www-data -R *

Add proper permissions and deploy once again

find . -type f -exec chmod 644 {} \;                // 644 permission for files
find . -type d -exec chmod 755 {} \;                // 755 permission for directory 
find ./var -type d -exec chmod 777 {} \;            // 777 permission for var folder    
find ./pub/media -type d -exec chmod 777 {} \;
find ./pub/static -type d -exec chmod 777 {} \;
chmod 777 ./app/etc
chmod 644 ./app/etc/*.xml

php bin/magento setup:upgrade
rm -rf var/cache/ var/generation/ var/page_cache/ var/view_preprocessed/ pub/static var/composer_home
php bin/magento setup:static-content:deploy
chmod -Rf 777 pub/ var/

Thank you 
Problem solved? accept as a solution and click Kudos.

[Vivekv2v]

Hello @smita_kagwade ,

​Thanks for your reply, I tried but it's not working​ for me. any other solution related to table changes (Attribute set). First it worked normally. After some time this problem happens automatically.

[Vivekv2v · Accepted solution]

Finlay I found solution

After run following query in Database the issue was resolved.

UPDATE `eav_attribute` SET `backend_model` = '' WHERE `eav_attribute`.`attribute_code` = 'msrp';

[sonstigesg405a]

Hi,

I'm using the following add-on to work with my shop: https://www.cobby.io

This tool is based on excel an allows me to control the shop with all given excel formulas. 

Just give it a try and you will spare a lot of time and energy!