Hi Jon,

If you want exclude specific file extensions to be uploaded to the media library then you can add the file extension(s) to the Disallow section in the umbracoSettings.config.

 <!-- These file types will not be allowed to be uploaded via the upload control for media and content -->
    <disallowedUploadFiles>ashx,aspx,ascx,config,cshtml,vbhtml,asmx,air,axd,swf,xml,html,htm,svg,php,htaccess</disallowedUploadFiles>

Hope this helps,

/Dennis

In order to cancel out large files, you could go about doing a class that derive from ApplicationEventHandler and hook up to MediaService.Saving event:

using System;
using System.Linq;
using Umbraco.Core;
using Umbraco.Core.Events;
using Umbraco.Core.Services;

namespace App.EventHandlers
{

    public class AppEventHandler : ApplicationEventHandler
    {
        const int MAX_SIZE = 100000;

        protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            MediaService.Saving += (sender, e) =>
            {
                foreach (var entity in e.SavedEntities)
                {
                    var property = entity?.Properties?.First(p => p.Alias.InvariantEquals("umbracobytes"));
                    if (property != null)
                    {
                        var size = Convert.ToInt32(property.Value);
                        if (size > MAX_SIZE)
                            if (e.CanCancel)
                                e.Cancel = true; // todo: explain cancel in notification
                    }
                }
            };
        }
    }

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