3.3. Why are User ID's prefixed with "i:0#.w" in LOGbinder for SharePoint?
In October 2014 a customer reported that LOGbinder for SharePoint was prefixing some usernames with what appeared to be a random string of characters. For example, instead of "test\jsmith" you may see "i:0#.w"|test\jsmith". Why is this happening and what does it mean? First of all, it's important to remember that LOGbinder is not creating this information. The User ID field comes directly from SharePoint. Secondly, these are not just random characters. This is actually the method SharePoint uses to identify the claim type being used. You can decode the claim type be reported using this Microsoft TechNet article. Occasionally, you may not see characters used as specified in the TechNet article. This is mostly because you are using a custom claims provider. For unidentified custom claims providers SharePoint will create a claim type starting with the value 500 and will increase in increments of 1 for each unidentified claims provider that is found. You can read more details about that in an article here.