[dwwright]

Originally Posted by BirdOPrey5

Weird because uploader.swf shouldn't be involved at all as this would be instead of the flash uploader. Unfortunately I can't test on PHP 7.1 but if you go to Admin CP -> Settings -> Options -> Message Attachment Options, make sure "Asset Manager - Enable" is set to Yes, Ajax Uploader by default.

Already set to that.

I do also get two errors just before the newattachment.php error of:
vbulletin_asset.js:11 vB_Asset :: NaN
vbulletin_asset.js:11 vB_Asset :: NaN

So could be an unrelated javascript error causing it to default to the flash plugin I guess.

Another strange behavior is that once I have images in the bottom tray of the dialog, the Insert Inline shows the correct number of images to insert are correct, but clicking the button does nothing, the image tags are not inserted into the post. If I close and re-open the dialog, the insert images will work at that point.