.mov files won't play on my new MacBook. Can't get them to Cloud

My .mov files will not play on my new MacBook. I looked for trouble-shooting, says to click in Finder and look for an app to open them/convert them. But they are already .mov files, so what would I convert to? I also cannot send them to the Cloud to play them there. Says they don't exist. Is there an old .mov and a new .mov I need to convert them to? Videos recorded on a iphone and stored on a Mac won't play on a Mac?

Your information is sketchy and confusing.

The MOV file extension refers to the file container—in this case the generic "QuickTime" file container. Unfortunately, an MOV file may contain any form of compressed data compatible with the codec configuration for the platform on which the file was created. In short, it may contain proprietary or third-party compressed data not supported by the computer you are now using. So, the first step is to determine what form of compressed data is stored in your MOV files that is not playing on your current system. You can try to determine using the Finder "Info" window, "Inspector" window for any media player that will open the file, or using a dedicated utility like "MediaInfo."

All current QTX media players support H.264/AAC MOV (distribution) files and ProRes422/LPCM MOV (archival and editing) files as the default standard while macOS High Sierra and iOS/tvOS 11 additionally support HEVC/AAC MOV files natively. Videos recorded on an old iPhone 4s should compatible with any current macOS unless security issues are detected or the data is corrupted. Newer iPhones operating under iOD 11 may be programmed (in the Camera app) to record video using the new HEVC (H.265) video format and if transferred from that iPhone to a pre-High Sierra macOS platform without resetting the iPhone Photos app to automatically transcode the video content as needed for compatibility with the the macOS device, they will not play in QTX/QT7 media players.

As to "Cloud" playback. once again what kind of data is stored in the files and under what operating system are you trying to play them back? As to "old" or "new" MOV files, if security ("atom") issues are detected, such files can sometimes be "fixed" by copying the data from the old MOV file to a new MOV file. As to "recorded on an iPhone and stored on a Mac won't play on a Mac," can you be more specific regarding the iPhone model, iOS version and macOS version? As previously mentioned, a pre-High Sierra Mac does not support HEVC content recorded on the newer iOS 11 iPhones and transferred to the Mac without transcoding to H.264 video compression. In these cases. either reset the iPhone to record using H.264 video, transcode to H.264 "on-the-fly" while transferring the files, or upgrade the macOS to High Sierra if supported.

In finder, right click shows empty 00.00 movie duration. Info has a file name.mov and just says “movie” for description. Suggestions for open with shows default QuickTime which doesn’t work, iTunes (no) Spotify, other-search App Store. I tried a converter Smart Converter Pro 2, it didn’t work.

Corrupted I suppose.

That doesn't sound good. Check the file size for the videos. A "00.00" time and file size of only a few KBs would indicate the data has been "lost" somehow while a "00.00" duration with a large file size may indicate a file that has been trim-edited and saved with edited playback pointers or is corrupted. The former might be salvaged if you can find a third-party player that ignores such stored edits. Unfortunately, your comment that nothing will open them likely indicates the files either contain no data at all, are limited to a single video frame, or, as you said, are corrupted. So I'd advise against getting your hopes up here.