When you’re blocked, you can’t find the other user in Facebook search results or see her profile or posts anywhere on Facebook.
Just because a user disappears from your friend list, however, doesn’t mean you were blocked. There are a few ways to investigate whether or not you were blocked, though there is no concrete way to discover who has you on a block list.
1. Conduct a Facebook search for the former friend using the search bar at the top of any Facebook screen. If the person has a common name, click the “See more results” link at the bottom of the short list of results that appears to open the full results screen.
Click the “People” link on the left side of the full search results screen and then apply one of the search filters, such as the location filter, to narrow down the search.
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If you still don’t see the person for whom you are looking, she has either blocked you or deactivated her account. If you do see her, then she just removed you from her friend list but didn’t block you.
2. Ask a mutual friend if she can still see the person’s Facebook account. If the mutual friend has also noticed that the user is gone from Facebook, then your missing friend has most likely deactivated her account.
If, however, the mutual friend can still see the user, then you have specifically been blocked from seeing the profile.
3. Conduct a Google search. Block settings don’t apply to public search engines, so if your former friend’s profile still exists, you can see the Google result for her Facebook profile even if you can’t view the profile.
Bear in mind, however, that some users have disabled their account from turning up in public search even when their profile is active.
The Google cache is also not updated in real time, so a deactivated Facebook profile may still turn up in results for a few days.