save for web not working

[grst]

I've been trying to use the save for web option to save a GIF, but I get the message "Could not complete this operation. An unknown error has occurred.":

 Before this, I was working on a GIF and saved for web without any issues. I didn't change any of the settings after saving that GIF, and I didn't change any of the settings while editing this one.
I tried to see if it was this particular project that was giving me issues, but now the save for web option doesn't work when I try to export any GIF, JPEG, PNG-8, PNG-24, or WBMP.
I've spent hours looking through forums and I've tried all the options (decreased image size, reduced resolution, ect.) but none have worked. I also deleted the program and reinstalled it, but that didn't change anything either. Both my Mac and Photoshop are up to date, but I still get this error notificaiton whenever I try to save for web. 

[silk-m]

Hi

Adobe Save for Web 13.0 Prefs may have been damaged. Please throw it away in the trash.

/Users/User Name/Library/Preferences/Adobe Save for Web 13.0 Prefs

Adobe Save for Web 13.0 Prefs is not updated when Photoshop is reinstalled.

Best,

[grst]

I just deleted the Save for Web 13.0 Preferences file but I'm still getting the same error message. 

[gener7]

Go into Preferences > Performance and checkmark Legacy Compositing. Restart Photoshop and see if that helps.

This may help: https://feedback.photoshop.com/photoshop_family/topics/photoshop_selecting_save_for_web_gives_error_...

There's a number of reasons addressed including oversized files.

Legacy Save for Web is a bit outdated and will soon be removed.

Try File > Export > Export As... for jpeg and png

[grst]

I just tried the first thing you said and no luck.

I've tried everything in the thread as well.

   Is there an alternative to Save for Web?? 

[pepenymi330671178]

You need updating to Photoshop 2020.

[Nancy OShea]

I never use GIF  except for animated ones and then only rarely.  That message usually indicates a memory problem.  Try reducing the image height, width and number of animation frames which also reduces file size

[rainboway]

I have the same issue. reducing size and lenght of the video doesn't change the situation. I have the most updated version of Photoshop and Mac Mojave. If saving for the web is outdated, how can you create an ANIMATED GIF from a quick time video then? I don't know of any other way of doing it. Thanks for the help 

[PECourtejoie]

Hello, is it only quicktime videos that cause the issue? smaller physical dimensions?

Does any other type of video work?