I've SharePoint 2013 farm with service pack 1 installed for SharePoint kb2880552 and can not install service pack1 for language pack it gives Error expected version of this product was not found in the system
1 Answer
For your issue, try to execute the installation on PowerShell window with PACKAGE.BYPASS.DETECTION.CHECK=1
Similar issue post for your reference:
https://www.afahru.com/2018/12/message-expected-version-of-product-was.html