How to find an error code
Every notice shows a code such as ERR-PARSE-001. While loading, the progress window shows a live log with bytes, speed, encoding and timing. Only if our support team asks, press F12 to open the browser console with the full log; add that log to a bug report.
Everything stays local
Mbox Viewer runs entirely in your browser. Even with an error, your file never leaves your device.
ERR-PARSE-001: the file could not be read
The file could not be parsed. It is probably incomplete or damaged, for example due to an interrupted download.
Fix ERR-PARSE-001
- Check that the file downloaded fully. An interrupted download from Google Takeout or a mail client is the most common cause.
- Export the mailbox again from the source and open the fresh copy.
- Is the file inside a zip or tar.gz? Open the archive directly in Mbox Viewer instead of unpacking it yourself.
ERR-DB-001: saving to your device fails
The app could not write to storage on your device, usually because space is full or storage is blocked.
Fix ERR-DB-001
- Free up disk and browser space.
- Close other tabs running Mbox Viewer.
- Go to Settings and choose Clear local database, then open the file again.
ERR-DB-QUOTA: the browser storage limit is reached
The browser sets its own storage limit, separate from your free disk space. With a very large archive that limit can fill up.
Fix ERR-DB-QUOTA
- In Settings, clear the local database to free up space.
- In Settings, request persistent storage so the browser does not clear your data at will.
- Optionally raise the in-memory threshold or open a smaller part of the archive.
ERR-PDF-001: the PDF could not be created
Something went wrong while creating the PDF.
Fix ERR-PDF-001
- Try the export again.
- If it still fails, export the message as HTML instead of PDF.
ERR-ATTACH-001: an attachment could not be saved
An attachment could not be saved to your device.
Fix ERR-ATTACH-001
- Check that downloads are allowed in your browser.
- Make sure there is enough free space.
- Then try again.
Notices that are not errors
Blocked script execution in about:srcdoc
Seeing this in the console? It is not an error. Each message is shown in a locked-down frame so hidden code never runs. Chrome prints that note for every locked-down frame, even for a message with no code. During normal use you never see it.
Direct import of Outlook pst and ost
Mbox Viewer opens Outlook pst and ost files directly, with no export or conversion first. The original folder structure, winmail.dat attachments and embedded Outlook messages (as normal attachments) are preserved. From pst and ost it also reads contacts, calendar appointments, tasks and notes, with a filter by item type.
Why does a large archive keep loading while I can already read?
There is no real size limit. For a large file Mbox Viewer switches to its built-in local database and keeps scanning in the background while you already read and search.
Can I open a pst file without Outlook?
Yes. Drag the pst or ost file straight into Mbox Viewer. You do not need Outlook and there is nothing to convert.
Which files can I open?
.mbox, .mbx and .mbox.gz, .eml and .emlx, Maildir folders with cur and new, Outlook .msg, .pst and .ost, and .zip or .tar.gz archives with any of these inside.
Where do I report a bug or request a feature?
At cloud-captains.com/mbox-viewer. Describe the problem briefly, with steps to reproduce and, if possible, the log from the console.
Back to getting started with Mbox Viewer.