Macbook Pro freezes in Time Machine

If this is your very first backup, or if you have not run Time Machine backup for more than two or three days, too many Folders have changed and Time Machine must do a "deep traversal". This typically takes four hours or more, just to compute what files have changed, before a single file is copied.

If you allow Time Machine to run more often, it uses a system data structure called the File System Event Store (which is finite in size) to tell which folders have changed Recently, and copying files can proceed almost immediately.

Time Machine's "claim to fame" is that it runs in the background, at low priority, so that you can keep doing your important work without interruption.

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The question about your Drive is fishing for whether your drive is getting so old and slow -- typically due to developing Bad Blocks -- that it could be slowing down the entire backup process.

Re-reading a Bad Block that comes clean at the last possible moment can take an additional quarter minute for each such block.

Running Yosemite 10.10.5 (Cant update to anything else ) 15.4 in Display, has a 750GB in it. On the time machine screen it gets to “PREPARING BACKUP” and nothing moves. The blue status line just ripples

what status shows in the control panel?

what MacBook pro 2009 screen size? does it have the original disk still installed?

what macOS?

All information is understandable and Thank You. Question, Would icloud have a part in this? Only after i linked 2 macbooks and iphone with icloud did i start having these issues.

Connecting those devices to iCloud would change a lot of files.

That may be what is taking so long.