If you are using a custom theme and are having issues with OpenStock, you'll need to have changes made to your theme to ensure that OpenStock works correctly with it. Our team can make the needed changes to your theme for you, simply visit our store to book in your patch.
Other Common Issues
The OpenStock module will almost certainly not work with ANY other module that alters product options.
If you receive the error "Warning: Cannot modify header information - headers already sent" when trying to save a product with a lot of option variants, you will need to ask your host to increase "max_input_vars".
Some users also have problems when they have lots of options such as when they save some of the data goes missing or variants duplicating every time you save the product. This is again related to the php setting "max_input_vars" - ask your host to significantly increase the value. Use a PHP info file to get your current value.