Preview generation stops with "An unhandled exception has been thrown:"

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---

### Steps to reproduce
1. I don't know
2.
3.

### Expected behaviour
When executing a command for preview generation the previews to be successfully  generated:
Commands used. 
sudo -u www-data php occ preview:generate-all -vvv
sudo -u www-data php occ preview:generate-all [username]



### Actual behaviour
Command execution stops almost immediately with "An unhandled exception has been thrown"

2025-10-16T14:13:49+00:00 Scanning folder /fhnt/files/Applications/TS10/ORG
2025-10-16T14:13:49+00:00 Generating previews for /fhnt/files/Applications/TS10/ORG/Subaru White Logo HD PNG - 1920x1080.png
An unhandled exception has been thrown:
TypeError: OC\Preview\Generator::generatePreviews(): Return value must be of type OCP\Files\SimpleFS\ISimpleFile, null returned in /var/www/nextcloud_vss/lib/private/Preview/Generator.php:190
Stack trace:
#0 /var/www/nextcloud_vss/lib/private/PreviewManager.php(182): OC\Preview\Generator->generatePreviews()
#1 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(210): OC\PreviewManager->generatePreviews()
#2 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(192): OCA\PreviewGenerator\Command\Generate->parseFile()
#3 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(190): OCA\PreviewGenerator\Command\Generate->parseFolder()
#4 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(190): OCA\PreviewGenerator\Command\Generate->parseFolder()
#5 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(190): OCA\PreviewGenerator\Command\Generate->parseFolder()
#6 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(170): OCA\PreviewGenerator\Command\Generate->parseFolder()
#7 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(116): OCA\PreviewGenerator\Command\Generate->generateUserPreviews()
#8 /var/www/nextcloud_vss/lib/private/User/Manager.php(629): OCA\PreviewGenerator\Command\Generate->OCA\PreviewGenerator\Command\{closure}()
#9 /var/www/nextcloud_vss/apps/previewgenerator/lib/Command/Generate.php(115): OC\User\Manager->callForSeenUsers()
#10 /var/www/nextcloud_vss/3rdparty/symfony/console/Command/Command.php(326): OCA\PreviewGenerator\Command\Generate->execute()
#11 /var/www/nextcloud_vss/3rdparty/symfony/console/Application.php(1078): Symfony\Component\Console\Command\Command->run()
#12 /var/www/nextcloud_vss/3rdparty/symfony/console/Application.php(324): Symfony\Component\Console\Application->doRunCommand()
#13 /var/www/nextcloud_vss/3rdparty/symfony/console/Application.php(175): Symfony\Component\Console\Application->doRun()
#14 /var/www/nextcloud_vss/lib/private/Console/Application.php(187): Symfony\Component\Console\Application->run()
#15 /var/www/nextcloud_vss/console.php(90): OC\Console\Application->run()
#16 /var/www/nextcloud_vss/occ(33): require_once('...')

What I've done and tested so far:
1. Checked folder's permissions - OK
2. Executed preview generation for a single files like this:
sudo -u www-data php occ preview:generate "/fhnt/files/Applications/TS10/ORG/Subaru White Logo HD PNG - 1920x1080.png"
and get "preview generated" with and no errors.
3. Reinstalled the app - no effect
4. Reset/regenerate the previews as explained in the "I want to reset/regenerate all previews" section of the readme - no effect.
5. Tested with single preview providers - no effect.

### Server configuration

**Web server:** Apache/Nginx
Nginx
The webserver stays behind Nginx Proxy Manager.

**Database:** MySQL/Maria/SQLite/PostgreSQL
MariaDB
**PHP version:** 8.2/8.3/8.4
8.3
**Nextcloud version:** (see Nextcloud admin page)
32.0.0, but I've noticed this behavior even before the update. For example 31.0.x
<details>
<summary>List of activated apps</summary>

```
If you have access to your command line run e.g.:
sudo -u www-data php occ app:list
from within your Nextcloud installation folder
```

</details>
Enabled:
  - activity: 5.0.0-dev.0
  - admin_audit: 1.22.0
  - app_api: 32.0.0
  - bruteforcesettings: 5.0.0-dev.0
  - circles: 32.0.0
  - cloud_federation_api: 1.16.0
  - comments: 1.22.0
  - contactsinteraction: 1.13.1
  - dashboard: 7.12.0
  - dav: 1.34.2
  - federatedfilesharing: 1.22.0
  - federation: 1.22.0
  - files: 2.4.0
  - files_downloadlimit: 5.0.0-dev.0
  - files_external: 1.24.0
  - files_pdfviewer: 5.0.0-dev.0
  - files_reminders: 1.5.0
  - files_sharing: 1.24.0
  - files_trashbin: 1.22.0
  - files_versions: 1.25.0
  - firstrunwizard: 5.0.0-dev.0
  - logreader: 5.0.0-dev.0
  - lookup_server_connector: 1.20.0
  - memories: 7.7.0
  - nextcloud_announcements: 4.0.0-dev.0
  - notifications: 5.0.0-dev.0
  - oauth2: 1.20.0
  - password_policy: 4.0.0-dev.0
  - photos: 5.0.0-dev.1
  - previewgenerator: 5.10.0
  - privacy: 4.0.0-dev.0
  - profile: 1.1.0
  - provisioning_api: 1.22.0
  - recommendations: 5.0.0-dev.0
  - related_resources: 3.0.0-dev.0
  - serverinfo: 4.0.0-dev.0
  - settings: 1.15.1
  - sharebymail: 1.22.0
  - support: 4.0.0-dev.0
  - survey_client: 4.0.0-dev.0
  - suspicious_login: 10.0.0-dev.0
  - systemtags: 1.22.0
  - text: 6.0.0-dev.0
  - theming: 2.7.0
  - twofactor_backupcodes: 1.21.0
  - twofactor_nextcloud_notification: 6.0.0-dev.0
  - twofactor_totp: 14.0.0
  - updatenotification: 1.22.0
  - user_status: 1.12.0
  - viewer: 5.0.0-dev.0
  - weather_status: 1.12.0
  - webhook_listeners: 1.3.0
  - workflowengine: 2.14.0
Disabled:
  - encryption: 2.20.0 (installed 2.20.0)
  - user_ldap: 1.23.0
<details>
<summary>Nextcloud configuration</summary>

```
If you have access to your command line run e.g.:
sudo -u www-data php occ config:list system
from within your Nextcloud installation folder
```

</details>
{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "XXXXXXXXXXXXX.xxx",
            "10.0.0.14",
            "localhost",
            "127.0.0.1",
            "::1"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "32.0.0.13",
        "overwrite.cli.url": "https:\/\/XXXXXXXXXXXXX.xxx\/",
        "overwritehost": "XXXXXXXXXXXXX.xxx",
        "overwritewebroot": "\/",
        "overwriteprotocol": "https",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "htaccess.RewriteBase": "\/",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "cron_type": "cron",
        "maintenance_window_start": 1,
        "maintenance": false,
        "default_phone_region": "BG",
        "simpleSignUpLink.shown": false,
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "587",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.local": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "timeout": 1.5
        },
        "theme": "",
        "loglevel": 2,
        "mail_smtpauth": true,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "enable_previews": true,
        "preview_max_x": 2048,
        "preview_max_y": 2048,
        "preview_max_memory": 512,
        "preview_max_filesize_image": 50,
        "enabledPreviewProviders": [
            "OC\\Preview\\Image",
            "OC\\Preview\\Movie",
            "OC\\Preview\\MarkDown"
        ],
        "memories.db.triggers.fcu": true,
        "memories.exiftool": "\/var\/www\/nextcloud_vss\/apps\/memories\/bin-ext\/exiftool-amd64-glibc",
        "memories.vod.path": "\/var\/www\/nextcloud_vss\/apps\/memories\/bin-ext\/go-vod-amd64",
        "memories.gis_type": 1,
        "memories.vod.ffmpeg": "\/usr\/bin\/ffmpeg",
        "memories.vod.ffprobe": "\/usr\/bin\/ffprobe",
        "data-fingerprint": "XXXXXXXXXXXXXX",
        "updater.release.channel": "stable",
        "app_install_overwrite": []
    }
}

### Browser

**Browser name:** Firefox/Chrome/Safari/…
Firefox
**Browser version:** 124/125/…
144.0
**Operating system:** Windows/Ubuntu/Mac/…
Windows 11
<details>
<summary>Browser log</summary>

```
Insert your browser log here, this could for example include:
a) The javascript console log
b) The network log
c) ...
```

</details>

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Preview generation stops with "An unhandled exception has been thrown:" #570

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Preview generation stops with "An unhandled exception has been thrown:" #570

Description

How to use GitHub

Steps to reproduce

Expected behaviour

Actual behaviour

Server configuration

Browser

Metadata

Metadata

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