When another app changes your file

When another app changes the file you have open, Unmarked shows the new version a moment later and keeps your place. The other app can be an AI assistant writing a report, a coding agent updating a README, a script, git, or another editor. It works in Read and Write, with Unmarked in front or in the background, and there's nothing to turn on.

What you see

The window updates about a quarter of a second after the other app finishes writing. While an assistant is still writing, the window keeps up about once a second, so you can read the document as it grows. Large files, over 100 KB, update every few seconds instead.

The status bar shows "Updated from disk" for a moment, so you know the change came from outside.

Your place stays put

In Read mode, the paragraph you're reading stays where it was on screen, even when text arrives above it. If you were at the end of the document, the window follows the new text as it's added.

In Write mode, the same line stays at the top of the window, and your cursor and any selection stay on their words. A table cell you're editing keeps the cursor when rows are added above it.

Your typing comes first

Unmarked never replaces text you're in the middle of typing. If you edited the document and the file also changed on disk, macOS shows its "changed by another application" alert about two seconds after you stop typing, and you decide which version to keep.

Updates also wait while you're presenting, dragging, or working in a link, image or Properties box. They arrive as soon as you're done.

Your own edits reach the file about two seconds after you stop typing, so the other app sees them too. More on saving.

An outside change starts a fresh undo history, so ⌘Z won't bring back the version from before it.

Reading a plan or report while an AI assistant writes it is a common use. Reading AI output on a Mac walks through it.

If the file moves or disappears

If the file is renamed or moved, Unmarked follows it to its new name or folder.

If it's deleted or can't be read, the window keeps showing what you had. When the file comes back, for example after you switch branches in git, the new version loads.