Unknown error uploading specific files

Nextcloud version (eg, 12.0.2):
Operating system and version (eg, Ubuntu 17.04): Linux 3.10.0-862.3.2.4.ELK.el6.x86_64 shared hosting with cpanel
Apache or nginx version (eg, Apache 2.4.25): Apache2 version not known
PHP version (eg, 7.1): 7.3.12

The issue you are facing:

Three specific PDF files cannot be uploaded into any folder by any user (admin or non-admin).
Each time I receive message “An unknown error has occurred” but no corresponding log entry.

These files are < 1MB

Changing the file name by a small amount – e.g. from “SCP S1 - Factsheet - Q3 2019.pdf” to “SCP S1 - Factsheet - Q3 2019-v1.pdf” – has no effect and the same error is received.
Changing the file name significantly – e.g. from “SCP S1 - Factsheet - Q3 2019.pdf” to “Factsheet - Q3 2019.pdf” causes no issues and the file is uploaded.
In fact, any file that is renamed as “SCP S1 - Factsheet - Q3 2019.pdf” will not upload, giving an “unknown error” message.

I have tried:

  • rebuilding from scratch (fresh db and filesystem) in the same subdomain. Same error.
  • rebuilding from scratch (fresh db and filesystem) in a different subdomain. Same error.

Is this the first time you’ve seen this error? (Y/N): Y

Steps to replicate it:

Using Windows 10 1903 + Chrome 78

  1. Using the files app, drag the file from Windows Explorer into the browser.
  2. Banner “Uploading” appears, changes to “A few seconds” then error message appears.
  3. Retry same steps using “+” -> “Upload file”. Receive same error message.

The output of your Nextcloud log in Admin > Logging:

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

    "instanceid": "***REMOVED SENSITIVE VALUE***",
    "passwordsalt": "***REMOVED SENSITIVE VALUE***",
    "secret": "***REMOVED SENSITIVE VALUE***",
    "trusted_domains": [
    "datadirectory": "***REMOVED SENSITIVE VALUE***",
    "dbtype": "mysql",
    "version": "",
    "overwrite.cli.url": "https:\/\/***REMOVED SENSITIVE VALUE***",
    "dbname": "***REMOVED SENSITIVE VALUE***",
    "dbhost": "***REMOVED SENSITIVE VALUE***",
    "dbport": "",
    "dbtableprefix": "oc_",
    "dbuser": "***REMOVED SENSITIVE VALUE***",
    "dbpassword": "***REMOVED SENSITIVE VALUE***",
    "installed": true,
    "allow_user_to_change_display_name": false,
    "skeletondirectory": "",
    "lost_password_link": "***REMOVED SENSITIVE VALUE***",
    "maintenance": false,
    "loglevel": 0

The output of your Apache/nginx/system log in /var/log/____:
Not currently available – hosting support to provide.

Additional system info:

Server configuration detail

Operating system: Linux 3.10.0-862.3.2.4.ELK.el6.x86_64 #1 SMP Thu May 24 16:26:56 CDT 2018 x86_64

Webserver: Apache (cgi-fcgi)

Database: mysql 5.6.41

PHP version: 7.3.12

Modules loaded: Core, date, libxml, openssl, pcre, zlib, filter, hash, pcntl, readline, Reflection, SPL, session, standard, cgi-fcgi, bcmath, bz2, calendar, ctype, curl, dom, mbstring, fileinfo, ftp, gd, gettext, gmp, iconv, imap, intl, json, exif, mysqlnd, odbc, PDO, pgsql, Phar, posix, pspell, SimpleXML, soap, sockets, sqlite3, tidy, tokenizer, xml, xmlwriter, xsl, zip, mysqli, pdo_mysql, PDO_ODBC, pdo_pgsql, pdo_sqlite, wddx, xmlreader, xmlrpc, imagick, ionCube Loader

Nextcloud version: 17.0.1 -

Updated from an older Nextcloud/ownCloud or fresh install:

Where did you install Nextcloud from: unknown

External storages: files_external is disabled

Encryption: no


  • OC\User\Database

Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36

 - accessibility: 1.3.0
 - bruteforcesettings: 1.4.0
 - cloud_federation_api: 1.0.0
 - dav: 1.13.0
 - federatedfilesharing: 1.7.0
 - files: 1.12.0
 - files_accesscontrol: 1.7.0
 - files_pdfviewer: 1.6.0
 - files_rightclick: 0.15.1
 - groupfolders: 5.0.4
 - logreader: 2.2.0
 - lookup_server_connector: 1.5.0
 - oauth2: 1.5.0
 - password_policy: 1.7.0
 - provisioning_api: 1.7.0
 - serverinfo: 1.7.0
 - support: 1.0.1
 - systemtags: 1.7.0
 - theming: 1.8.0
 - twofactor_backupcodes: 1.6.0
 - workflowengine: 1.7.0
 - activity
 - admin_audit
 - comments
 - encryption
 - federation
 - files_external
 - files_sharing
 - files_trashbin
 - files_versions
 - files_videoplayer
 - firstrunwizard
 - gallery
 - nextcloud_announcements
 - notifications
 - privacy
 - recommendations
 - sharebymail
 - survey_client
 - text
 - updatenotification
 - user_ldap
 - viewer

I think I may have the same issue. Were you able to hone in on what might be special about those files? Is it just the filename?

Same Problem here. Filesize dont matter. Happens with some mp3, mp4 and zip … Problem is with browser (Edge and Chrome) and also with the Windows Client 2.6.x … with some files when i Restart the sync many time the upload works. the interresting Thing is with Client 2.3.x there are no Problems. pls help