Download a sample file of size that is bigger than 28.6mb and less than ~4gb (this is the hard cap for IIS Express) this should work with any uploadable filetype, like jpeg, png, mp4 etc.

Modify the maxAllowedContentLength setting in the web.

Run umbraco using IIS, kestrel seems to work fine You have 3 available options to increase the file upload limit: 1.

To increase the upload limit add an appropriate section to your web.config file and specify the limit: In the case of IIS 7. By default, the IIS connection time-out setting is 120 seconds. By default maximum upload size is set to 4096 KB (4 MB) by ASP.NET. I've tried this on 9.0.0 and we actually get a visible error in the browser, not just the console, but still an error nonetheless Steps to reproduce Increase the connection time-out setting in IIS while uploading large files, there are chances that the request will timeout. Seems the file is to large and it hits the cap, there should be no cap after the fix in #11052 Specifics This can be checked/changed in the Request Filtering section of IIS Manager. When trying to upload a mp4 file to the media section, with a file size of 200mb, you're unable to upload the file, this will not give any visible errors of any kind, only if you open dev tools and look at the console you get this error: IIS may also limit the file sizing for upload. 3) you can then go in the IIS to set read and write permissions for it.

Which exact Umbraco version are you using? For example: 9.0.1 - don't just write v9 a) Right click the folder click sharing and security. You can increase the maximum file size by modify the maxAllowedContentLength setting in the web.config file: With the above maxAllowedContentLength, users can upload files that are 2 GB in size.

Uploading Large Files to IIS