Will a screen repair wipe my data on my Macbook? Also, yellow patches - Please explain!

This backup error can often be fixed by doing the following. Turn off TimeMachine. DoubleClick on the TM hard drive. Double click on the Backups.backupdb. If there's another folder, open it. Arrange by date or look for the file that looks something like this: 2019-04-03-0023.inProgress. Trash it and empty the trash. Turn TimeMachine back on. If this doesn't work you can do 1 of 2 things (I prefer the second.) 1) erase the TM drive and start over or 2) start using a new drive for TimeMachine.

I'd take it to get the display fixed.

Time machine taking too long:

There is a system data structure of finite size that maintains an accurate list of what folder have recently changed, called the File System Event Store. Since it is a finite size, it cannot record these changes forever. If you have attached your drive and let it run in the last few days, your backup (of whatever size) will generally move right along and make progress.

If you have put off allowing Time machine to write to the Backup drive for more than about three days, the File System Event store will be incomplete (stale). This forces Time machine to do a 'Deep Traversal' -- examining the last-modified date on every file on the backup and every file on your drive, and adds an elapsed time of as much as four hours.

Executive summary: backup up at least every other day and you won't have this problem.

Service:

Whenever you submit your MacBook Pro for service, you should presume your boot drive (now soldered to the mainboard in recent MacBook Pro) will NOT be coming back to you, and your files will exist ONLY on your backup(s). If they do come back, and you don't have to restore them from backups, then 'Merry Christmas'.

Best practice is to never send your computer for any kind of service unless you have a reliable backup, preferably two. My two "mission-critical" Macs each have two backup drives attached. One creates Time machine backups and the other uses Carbon Copy Cloner to generate a bootable clone of my hard drives every morning.

TM works by backing up all the files that have changed or are new since the last backup. Since 4 plus months have passed the preparation stage will take much longer than usual. Your backup stalled for some reason and I explained how to reset it. If you’ve done that and the backup doesn’t progress beyond preparing after 3 hours you probably won’t get another backup on that drive.

If that does happen i strongly recommend getting a new drive rather than erasing this one.

kc_7865 wrote:

I havent backed up since 27th December 2018. Is this why preparing backup is taking such a long time?

yes, that is exactly why, unless you get an error message that something else is wrong.

Time machine is set up to do its work at low priority in the background. It does things in a particular order to avoid deadlock when too little disk space is available.

First, it determines What needs to be saved, and its size. Then it check to see if that much space is available on the Backup drive. If not, it consolidates oldest backups to make more room, and may eliminate oldest backups. Only when it can tell there is enough room does it begin transferring data.

Because of the way it works, it cannot overlap any of these steps. When you wait too long backup, computing the size of what needs to be backed up takes quite a while. The actual elapsed time depends on the speed of the drives to be backed up and the speed of the backup drive.

Error message I was referring to are caused by completely different issues encountered by Time machine. As long as Time machine does not have different problem that precludes its working properly, calculating the size of the backup can proceed in the usual way, which takes many hours if you have not connected the backup Drive recently.

Below is a link to part one (of five) short, articles written by the late James Pond on how Time machine works internally. His large set of illustrated, approachable articles on all things Time Machine were complete when Time machine stopped changing, so despite references to older versions, they are still applicable today:

.Pondini's How Time Machine Works its Magic

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