`Previews let you view images, videos, audio files, and documents directly in your web browser without downloading or requiring desktop applications.
When you open a preview, the file appears in a dedicated viewing panel. You can move to the previous or next file in the directory using the arrow keys or the < and > navigation buttons.
Open and Navigate Previews
To open a preview, click the file name from a directory listing. Alternatively, select the file and choose View Details from the right-button menu or the toolbar.
Once open, navigate between files in the same directory.
Microsoft Office documents open in the Microsoft 365 viewer. You can preview these files in the following ways:
Sidebar Preview — displayed in the right-hand info pane under the Preview tab.
Full-Screen Preview — select Expand from the Sidebar Preview to open the document in a full-page overlay.
Media and Document Controls
Audio and video previews include controls to play, pause, mute or unmute, adjust volume, and switch to full-screen mode. For multipage documents, use your mouse scroll wheel to move forward and backward through pages.
How Document Preview Works
Documents are previewed as PDFs, except supported Microsoft Office and OpenDocument files, which open in the Microsoft 365 viewer for a high-fidelity preview directly in the browser without downloading the file.
The Microsoft 365 viewer renders the following file types:
PowerPoint: odp, pot, potm, potx, pps, ppsm, ppsx, ppt, pptm, pptx
Excel: csv, ods, xls, xlsb, xlsm, xlsx
Word: doc, docm, docx, dot, dotm, dotx, odt, rtf
OneNote: one, onetoc2
Visio: vdw, vsd, vsdm, vsdx
Note: Visio and OneNote files can only be viewed with the Microsoft 365 viewer.
Note: If Microsoft 365 previews are disabled for your account, all documents use the standard PDF previewer.
Note: If a document conversion takes longer than 25 seconds, you can choose to download the file.
Edit Microsoft Office Files in Web Access
Web Access supports editing for select Microsoft Office file types using Microsoft 365 for the web. Editing opens in a new browser tab and supports real-time co-authoring.
Microsoft 365 File Types Supported for Editing
PowerPoint: pptx, ppsx
Excel: xlsx, xlsm, xlsb
Word: docx, docm
Start an Edit Session
You must be logged in to Web Access to edit a file.
To edit a supported document, follow these steps:
Open the file in Sidebar Preview or Full-Screen Preview.
Select Edit in Word/Excel/PowerPoint for the web.
The file opens in a new browser tab.
Co-Author Files in Real Time
Multiple users in the same Web Access installation can edit a document simultaneously.
While co-authoring:
Presence indicators (icons or avatars) show who is currently editing.
In many cases, cursor or selection highlights are visible, depending on the document type and Microsoft 365 behavior.
Changes appear in real-time.
No manual merge is required.
How Saving and Sync Work
Changes are saved automatically while you edit.
If you close the browser tab, your latest edits are typically already saved.
If your connection is temporarily interrupted, Microsoft 365 continues attempting to sync and resumes saving when the connection is restored.
How Edit Conflicts Are Handled
If a document is modified outside of Microsoft 365 while you are editing, Microsoft 365 might detect a conflict.
If a conflict is detected, the following occurs:
Your edits are preserved.
Web Access keeps your version and renames the file to indicate a conflict.
You can manually compare and reconcile differences between versions.
Performance Considerations for Preview and Editing
Large or complex files, especially spreadsheets or presentations, might take longer to open.
If editing performance is slow, close other browser tabs and reload the editor tab.
File Types Supported for Preview
The preview in Web Access supports the following types of files:
Images: jpg, jpeg, gif, bmp, png, svg. Images with the TIFF and TIF extensions are supported in Safari.
Videos: mp4, m4v, mov, webm.
Note: If the browser does not support the video codec, the video cannot be played natively.
Audio: mp3, wav, ogg.
Documents: txt, pdf.
Unsupported File Types and Download Behavior
If your browser does not support the file format, you are prompted to download the file instead.
Note: Documents not using the Microsoft 365 viewer must be smaller than 250 MB to be eligible for preview. For Microsoft 365 viewer limits, see: https://learn.microsoft.com/en-us/microsoft-365/cloud-storage-partner-program/faq/file-sizes.