Nobody can tell you anything without exact system info or other technical details like exact versions of AE - the one you are using now and the one the project was created with just as well as specific info about comp settings, effects and features used and so on. Just saying that it doesn't work is of no use to anyone.
Thanks @Mylenium for good questions. Here's some more info -
The project was originally created in version 13.5.1 (mac 64) and now is being opened and converted to work with the latest version of After Effects.
There are a few dozen comps in the file. Sadly some of the footage associate with the file was lost due to a hard drive failure a few years ago. I have replaced the files sans a few and that issue seems to be working its way out. The downside is that because AE won't let me successfully save the file after converting it (when it does save it's a blank file with no comps) due to the error. This means when I open the file and replace and repair the missing content that work is for not and isn't able to be saved.
Also strangely enough the comps don't seem to update or show anything in the comp preview panel. Meaning, when I change aspects of the comps I don't see any changes in the window displayed.
It also lists three plugins as missing - DE ElectricArcs, DE Glower and DE Sparks which are all DigieEffects plugins. However, I have the plugins still in my system the issue is that at some point DigieEffects updated the plugins to be named without the DE. It also seems that they removed the Glower plugin.
Maybe the issue is I need to track down the plugins that are missing and try them out? I have already contacted DigieEffects tech support and have heard nothing.
Here is the troubled file in question in case anyone is curious - https://dl.dropboxusercontent.com/u/433483/AFD%20GO%20-%20ClassRoom.aep
It's a very odd situation!
The non-updating comps is a known issue with some legacy projects. I'm not a Mac person, but it seems related to changes in the render pipeline and are very specific to some versions of OSX. You might try to install an older version of AE CC 2017 to bypass the problem. If the old effects are the issue, simply remove them. Open the project with capslock to prevent screen refresh, then copy and paste the keyframes to the new effects or some dummy expression controls and delete the original effect. This might allow to actually see something.
Unfortunately opening the older project and removing the plugins and keyframes didn't work. Any other ideas?
Does importing the old project into a new one help?
Are you still facing this problem? If not, let us know how you solved it. If so, please let us know so we can assist you further.
I was able to resolve it by calling tech support and emailing my file to be repaired or fixed. Seems to be working ok now. thanks!