[Bug] PDF viewer fails to render on Chrome mobile (Android) — shows download prompt instead of preview

[z0rg0n]

Initial Checklist

• I understand this is a bug report and questions should be posted in the Community Discussions
• I searched issues and couldn’t find anything (or linked relevant results below)

Bug Description

The built-in pdf-viewer app fails to render PDFs on Chrome for Android. Instead of displaying the PDF inline, it shows a UUID-style filename and an "Open" button that triggers a download.

The same PDFs render correctly in:

• Firefox on the same Android device
• Chrome on desktop
• Firefox on desktop

I've tested it on multiple pdfs with text and images.
Android version 16

#1896 — Similar report (PDF preview broken), but was closed. The mobile Chrome case does not appear to have been addressed.

Reproduction Steps

1. Open the OpenCloud web UI in Chrome on Android version 16
2. Navigate to any PDF file
3. Click to open the PDF — the pdf-viewer app loads
4. Instead of rendering, a UUID and "Open" button are shown

Expected Outcome

PDF renders inline in the pdf-viewer, as it does on desktop browsers and Firefox mobile.

Actual Outcome

PDF does not render. A blob UUID is displayed with a button that triggers a download.

[JammingBen]

The web client fully utilizes the browser's PDF viewer. Are you sure that your mobile Chrome browser on Android supports displaying PDFs? AFAIK this is a relatively new feature, maybe Chrome/Android needs an update?

[z0rg0n]

Here's a bit more info on what I tested on:

Chrome version:
146.0.7680.177

Operating system:
Android 16; Pixel 9 Build/CP1A.260305.018

It's showing as up-to-date in my google play store. It seems like there are newer version of chrome available. I'll try to get those installed and tested as well.

[vik583]

Same here. Works on Desktop in Chrome and Firefox. On mobile it works in Firefox but not in Chromium based ones like Vanadium or Vivaldi.