While implementing Order processing in our sandbox, I ran into the scenario where a test user is able to create an Order for a certain account, can select the relevant Price Book and sees all the Products from that (standard) Price Book.
Unfortunately, after selecting the Products to add to the Order, and clicking “Select”, the user gets the generic “Insufficient Privileges” error message.
Initially, I was pointed to User can’t add product to an opportunity – error: insufficient privileges?, but the caveats in that knowledge article did not apply.
The end result was the creation of a ‘Known Issue’: Insufficient Privileges when adding Order Products from Standard Pricebook by Salesforce. At the time of writing this post, the status of the issue is ‘Under Review’.
The workaround I implemented was to grant the user Edit rights on Product and implementing validation rules to prevent regular users from actually changing any fields for a Product.