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Your LimeSurvey version:  Version 5.3.23+220705
Own server or LimeSurvey hosting: self-hosted
Survey theme/template: custom - fruity based
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When a response is submitted and the file upload question has any selected attachments, then the survey response is not saved in the MySQL table. The issue is likely related to the way the image/file upload is handled which in turn is breaking the SQL INSERT statement, because I a still getting an email notification that a new response has been submitted, although it being without a valid response ID (see the link from the email below) which results in a PHP 500 error citing bad syntax.

sub.domain.com/index.php/responses/view?surveyId=466989&id=

This only happens if the file upload has any attachments, everything works as it should if there is no file upload present in the response. I checked the allowed filetypes of the file-upload question and see no issue (attachment is a JPG file), next I am trying to mess with the php.ini settings for file_upload_size but dont think this is related since the attachment is only a few KB in size.

Any suggestion on where to look in regards to debug? Perhaps there is a log that would catch this?
Thanks

Another symptom I just found is that the max file size is set to 2048KB (=2MB) even though question setting is set to 10000 KB and my PHP.ini has upload_max_filesize and post_max_size set to "10M". I cannot find the "max_filesize" settings that is referenced here . There are several other users with the same issue but no apparent solution from 6 years ago ( see here ).

I am running PHP 7.3, both the php.ini settings and question settings have been adjusted, max_filesize setting is not present in PHP 7.3, and memory_limit is at 1 which technically allows up to 128MB memory usage and is not related to this issue. Any other settings besides php.ini that need to be amended?
Thanks

Edit: am I going crazy or am I unable to edit my posts anymore?

Normal users can't edit their posts here in the forum.

Checked the release notes and there has been some fixing going on around the file upload question, maybe a bug made it into the function, while they fixed the other bug:

-Fixed issue #18092: File upload show title/comment=off not yet fully respected (#2427)

community.limesurvey.org/release/220705/

In the following releases I couldn't see any fix that was about the file upload question. Usually I'd ask to do an update to the latest version, before submitting a bug report, which is still a good idea.

But chances that this has been fixed in the meanwhile are minor, given that "file upload" was not mentioned in the release notes since your version.

I would suggest to create a bug report.

Will do that, thank you.