If you think your content has been deleted …
… it might not be, but it’s a pain in the ass to access.
Tumblr said that they would not delete content (posts). Instead posts would be set to “posted privately” if the content violates their community guidelines.
If the reason that you believe your content has been deleted is because it is no longer in your archive, note that when posts are set to “private”, they are no longer accessible through your archive.
As a result, the only way to access a post that Tumblr has reset to “private” is by scrolling though your blog to find it chronologically.
If want to find something old and you don’t want to scroll though thousands of posts to find it, this is what I did:
In your browser, change your settings to turn off “endless scrolling”. This is under the advanced settings to change your appearance. Alternatively, use a theme that has page numbers. When you are in a browser (not the app) you can jump back months at a time by changing the page number in the URL and then scroll and look from that point. This is helpful if you are looking for something specific and have a rough idea of when you posted it.
It is not a complete solution but it makes it a little easier to find things. Don’t shoot the messenger, I’m just pointing out what worked for me.
