[Webdav] Mountain Duck 5.0.2 removes file content

[gharlan]

Describe the bug
The bug appears since Mountain Duck 5.0.2. When adding a file to a webdav mount, mountain duck uploads the file correctly, and then removes the content with a second PUT call.

To Reproduce
Steps to reproduce the behavior:

1. Connect to a webdav server (via new "integrated" mode)
2. Add a file to a directory

Expected behavior
The file should not be empty after upload.

Desktop (please complete the following information):

• OS: macOS 26
• Mountain Duck 5.0.2

Log Files
mountainduck.log

Additional context
I had a look to the requests via Charles Proxy.

Mountain Duck correctly adds the file to the webdav server:

PUT /webdav/Gregor%20-%2033/test.jpg HTTP/1.1
Expect: 100-continue
Content-Length: 76283
Content-Type: image/jpeg
Host: [...]
Connection: Keep-Alive
User-Agent: Mountain Duck/5.0.2.28022 (Mac OS X/26.0) (aarch64)
Accept-Encoding: gzip,deflate
Authorization: [...]

[File content]

Then multiple PROPFIND/PROPPATCH calls are made. The last one before removing the file content is this one:

PROPFIND /webdav/Gregor%20-%2033/test.jpg HTTP/1.1
Depth: 0
Content-Type: text/xml; charset=utf-8
Content-Length: 99
Host: [...]
Connection: Keep-Alive
User-Agent: Mountain Duck/5.0.2.28022 (Mac OS X/26.0) (aarch64)
Accept-Encoding: gzip,deflate
Authorization: [...]

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><propfind xmlns="DAV:"><allprop/></propfind>

Response looks like this:

HTTP/1.1 207 Multi-Status
Date: Fri, 26 Sep 2025 09:37:59 GMT
Content-Type: application/xml; charset=utf-8
Transfer-Encoding: chunked
Server: nginx
Cache-Control: max-age=0, must-revalidate, private
Content-Security-Policy: default-src 'none'; base-uri 'none'; connect-src 'self'; font-src 'self'; frame-ancestors 'none'; frame-src 'self'; img-src 'self' data:; script-src 'self'; manifest-src 'self'; style-src 'self' 'unsafe-inline'
Expires: Fri, 26 Sep 2025 09:37:59 GMT
X-Sabre-Version: 4.7.0
Vary: Brief,Prefer
DAV: 1, 3, extended-mkcol, 2
Connection: keep-alive

<?xml version="1.0"?>
<d:multistatus xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns"><d:response><d:href>/webdav/Gregor%20-%2033/test.jpg</d:href><d:propstat><d:prop><d:getlastmodified>Fri, 26 Sep 2025 09:37:53 GMT</d:getlastmodified><d:getcontentlength>76283</d:getcontentlength><d:resourcetype/><d:getetag>&quot;a2d1ebcfb3b8cf04a8abb4bbb72405bef6b2aac8&quot;</d:getetag><d:getcontenttype>image/jpeg</d:getcontenttype></d:prop><d:status>HTTP/1.1 200 OK</d:status></d:propstat></d:response></d:multistatus>

And then Mountain Duck removes the file content (empty body, Content-Length: 0):

PUT /webdav/Gregor%20-%2033/test.jpg HTTP/1.1
Content-Length: 0
Content-Type: image/jpeg
Host: [...]
Connection: Keep-Alive
User-Agent: Mountain Duck/5.0.2.28022 (Mac OS X/26.0) (aarch64)
Accept-Encoding: gzip,deflate
Authorization: [...]

---

The issue disappears after downgrading to Mountain Duck 5.0.1.

[ylangisc]

The log file unfortunately is almost empty. Can you please enable debugging logging, reproduce the issue and post the log file again? Feel free to send it to [email protected].

[dkocher]

We have identified the issue and will issue a fix in version 5.0.3 available later this week. It is reproducible for WebDAV servers that do not support modifying file metadata using PROPPATCH.