How to repair a serialized string which has been corrupted by an incorrect byte count length?

Question

I am using Hotaru CMS with the Image Upload plugin, I get this error if I try to attach an image to a post, otherwise there is no error:

unserialize()

Answer 1

There's another reason unserialize() failed because you improperly put serialized data into the database see Official Explanation here. Since serialize() returns binary data and php variables don't care encoding methods, so that putting it into TEXT, VARCHAR() will cause this error.

Solution: store serialized data into BLOB in your table.