OpenPreview Support
A few useful shortcuts, answers, and a direct way to get help.
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Common questions
Which files can I open?
Markdown (.md and .markdown), JSON, plain text, and text-based source files. Binary formats such as PDF, Word documents, and images are not document editing formats in OpenPreview. Use Command-O or drag files into the window.
How do I switch views?
For Markdown, “原文” means source and “预览” means preview. For JSON, “格式化” means formatted text and “结构” means structure. The current app interface is primarily Simplified Chinese.
How do split views and comparison work?
Right-click a tab and choose a left/right or top/bottom split. To compare two files, first show a different file in each pane, then click the comparison icon next to Edit at the top right. Click again to end comparison. Left/top is reference; right/bottom is current.
Where is search?
Command-F searches the current file. Control-Command-F searches open files. Command-G moves to the next result and Shift-Command-G to the previous one. Tree and comparison views may switch to source for searching.
When are changes saved?
Files open read-only. Command-E enters editing; Command-S saves, and Shift-Command-S opens Save As. Edits are not automatically written to disk. Closing modified work offers Save, Don’t Save, and Cancel. Unsaved drafts are not a backup or crash-recovery system.
What if another app changes a file?
If you have a draft, OpenPreview warns before overwriting a changed file. Keep the draft and use Save As, or review the disk version. Always keep your own backups.
Why are preview or comparison unavailable?
The read limit is 32 MiB per file. Content over 1,000,000 UTF-8 bytes uses simplified text mode. Detailed comparison is limited to a combined 30,000 lines and 2,000,000 UTF-8 bytes across both files; JSON nesting is limited to 64 levels. Comparison also requires two different files in a split layout.
How are Markdown images opened?
Click an image placeholder. Local images require permission for their folder. Remote images first ask permission for the current document and contact the image server only after you allow loading. Images open in a separate preview window. Remote loads have a 20-second request timeout and a 10 MB download limit; not every relative resource or Markdown extension is supported.
Is there a subscription?
No. OpenPreview is planned as a one-time paid Mac App Store download, with no in-app purchases. It has not launched yet. Store pricing and availability will be listed when it is released.
How do I remove local records?
Close documents when finished and save anything you want to keep. macOS may retain recent-file entries, window preferences, and system networking caches. Removing the .app alone does not guarantee those records are erased. Your original files remain yours; contact support for help removing app-specific local records.