Unserialize error at offset x in 3.0.1


I have upgrade from 2.4.6. to 3.0.1. I get one or more of “unserialize(): Error at offset…” for each page which is loaded in my browser. My old config file char set was as follows:

client_charset = utf-8
connection_charset = utf-8
database_charset = utf-8
charset_normalization = Off

I have tried the default values also.

These match with my new config file. I tied matching them before doing the actual upgrade. What else I can check?

Actually I think it is irrelevant to upgrade itself. because I get the error even on install and installUpgrade pages.


Hi @salehig,

Double-check your configuration file. Your connection_charset and database_charset settings should be utf8, not utf-8.

Alec Smecher
Public Knowledge Project Team

Thanks @asmecher. It worked for me. It would be great to have a description text for those tags in config.TEMPLATE.inc.php file. Because client_charset default value is utf-8 and it’s a bit confusing.