Time Machine won't back up

[grimsargh]

Hi there, over the last month my Time Machine backup has been sporadic and then finally said the backup disk was full so I purchased a new 2T LaCie external hard drive. TM backed up successfully the first time and then about 6 further backups and now I am back to this message "Time Machine could not back up the disk “Macintosh HD - Data” because it is nearly full." I also am not able to update to Monterey since I am running out of space on the computer and wondering if this might have something to do with it. My current computer has 2 slots for memory and both are in use for 16 GB. I am not sure I can replace these two memory slots with larger ones, would that be feasible? Would that then make the TM work also? Information on system and computer below:

Model Name: iMac OS: OS 11.6 The iMac is showing 2.7GB available of 499.96GB LaCie Backup: 1.56 TB available of 2 TB
Model Identifier: iMac18,2
Processor Name: Quad-Core Intel Core i5
Processor Speed: 3.4 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 16 GB in 2 8GB slots

Is TM telling me is can't back up my computer HD and if so why would that be. Sorry for the ramble but I know I will get good info and recommendations. How I wish I were still in Victoria with all the Apple help available there, the only Apple store I have available is quite a drive, not to mention they haven't opened up totally yet and only with appointments if you can get one.
Thanks for listening. Kaye

 

[DaveWT]

If your 2 memory slots have 16 GB of memory you probably OK for memory, unless you are doing some extreme video stuff or something. This has nothing to do with the message “Macintosh HD - Data” because it is nearly full."
Your statements of a new 2 T LaCie drive and then 2.7GB available of 499.96GB LaCie Backup have me confused. When you purchased the 2 T LaCie drive it probably came formatted in a Windows format. Did you use DisK Utility to reformat it for the Mac before you started using it for ™ backups? It sure looks like you aren't getting 2 Tb available.

You probably should make sure the format is set to use the Guid Partition Map and APFS format with only a single partition to get the entire drive available.

 

[grimsargh]

Thanks for the response DaveWT, I obviously didn't make it clear, the 2.7GB available of 499.96 GB is the iMac harddrive, the LaCie has 1.56 TB available of 2 TB. The two memory slots are 8GB each for 16GB. I have not partitioned the LaCie so it has the total 2T available. I did not use Disk Utility as it was supposed to be already formatted for Mac, probably a mistake. My other question was if I am able to remove the two 8GB and put in two new ones of higher GB. Am currently of the mind to use Disk Utility, wipe the LaCie and format as you suggest but not done that yet.

 

[DaveWT]

Sorry, I misread the details of the drive sizes... If it was advertised as formatted for Mac then you probably can assume it really is. If it was just advertised as for Windows or Mac then it is good to check as it is probably formatted for Windows. But if you have 1.56 TB available on the external, then I don't know why Time Machine thinks it is full. I do not know enough about the inner workings of Time Machine to know if it needs a bunch of temporary extra space on the internal drive while doing backups and that may be the reason it is complaining of a full disk (i.e. the internal is full, not the external.) Perhaps someone else will jump in here.

The reason you can't update to Monterey is because your internal drive is so full. You would need to offload a lot of stuff to an external drive first, free up internal space and then update to Monterey, followed by putting back the stuff you temporarily moved off. Photo and Video libraries are the best choices to make a real difference there.

I really can't see why you would need more than 16 GB of memory for normal use. That is what I have in my iMac and have never seen a need to go beyond that. If you are curious launch Activity Monitor (in the Utilities Folder) and click on the "Memory" tab at the top. It will show what apps are using the most memory, and at the bottom a little box that shows how much of your 16 GB is actually in use at that moment.

 

[chas_m]

1. Your RAM is fine and has zero to do with this issue. Don’t confuse memory (RAM) with drive capacity (storage).

2. Your issues are 100 percent due to overfilling your storage. That is waaaaay too little space for the Mac to operate correctly. As a rule of thumb, one should always leave at least 10 percent of storage available for working/temporary use by the computer itself. You are 48GB short of that goal!

Time Machine needs some working space to safely transfer files, so that’s why you are getting the error message. Go through and delete any videos you don’t need or other very large files so you have at least 50GB free space on the boot drive at all times, and not only will Time Machine start working again but you’ll be able to update to Monterey. AND the machine will generally work better.

 

[grimsargh]

Sorry, I misread the details of the drive sizes... If it was advertised as formatted for Mac then you probably can assume it really is. If it was just advertised as for Windows or Mac then it is good to check as it is probably formatted for Windows. But if you have 1.56 TB available on the external, then I don't know why Time Machine thinks it is full. I do not know enough about the inner workings of Time Machine to know if it needs a bunch of temporary extra space on the internal drive while doing backups and that may be the reason it is complaining of a full disk (i.e. the internal is full, not the external.) Perhaps someone else will jump in here.

The reason you can't update to Monterey is because your internal drive is so full. You would need to offload a lot of stuff to an external drive first, free up internal space and then update to Monterey, followed by putting back the stuff you temporarily moved off. Photo and Video libraries are the best choices to make a real difference there.

I really can't see why you would need more than 16 GB of memory for normal use. That is what I have in my iMac and have never seen a need to go beyond that. If you are curious launch Activity Monitor (in the Utilities Folder) and click on the "Memory" tab at the top. It will show what apps are using the most memory, and at the bottom a little box that shows how much of your 16 GB is actually in use at that moment.

Thanks again, DaveWT, I am in the process of removing some of my files onto a separate hard drive for hopefully safe storage, and then I shall use that to store video's I wish to keep also. Perhaps when done this will solve my problems. I had forgotten about the activity Monitor and when I look at that it shows 9.39 GB of memory in use of the 16GB. So will continue to work on removing some very old stuff that I probably don't need anymore. Kaye

 

[grimsargh]

1. Your RAM is fine and has zero to do with this issue. Don’t confuse memory (RAM) with drive capacity (storage).

2. Your issues are 100 percent due to overfilling your storage. That is waaaaay too little space for the Mac to operate correctly. As a rule of thumb, one should always leave at least 10 percent of storage available for working/temporary use by the computer itself. You are 48GB short of that goal!

Time Machine needs some working space to safely transfer files, so that’s why you are getting the error message. Go through and delete any videos you don’t need or other very large files so you have at least 50GB free space on the boot drive at all times, and not only will Time Machine start working again but you’ll be able to update to Monterey. AND the machine will generally work better.

Thanks, Charles, I do get confused with the RAM thing. I don't have many video's and what I do have are instructional and not available online anywhere so am in the process of removing those to an external drive, it may be a bit of a long process because they aren't all in the same location. Never mind, a good project for what promises to be a snowy weekend where I am located. I must also clean off my desktop as well, things build up on there also and I know that isn't ideal either. I worry about losing all my genealogy research files, which does contain photographs, if an external drive fails so perhaps I need a back up of the backup. Appreciate the assistance. Kaye

 

[grimsargh]

Just a followup on my storage problem, although I haven't added Time Machine into the mix yet, I can say I was able to update to Monterey this morning after having removed one particular section of my sewing files which contained video's. I will continue to prune things as I go along and am very thankful for the support I get from VMUG members. Thanks.

 

[grimsargh]

Just an update on my storage problem. Even after removing a whole bunch of old stuff and video's I was continuing to be shown as using over 11 GB of my available 16 so was at a loss what to do to solve it. However, along comes the recent update and yesterday I installed it, lo and behold I am now running just over 5GB, still baffled by why that is but thankfully things are better.

 

[DaveWT]

The reboot that happened as part of the update cleared a lot of RAM being used for cached files etc. so it then showed less RAM being used after the update. It will likely grow as you use the Mac.

 

[grimsargh]

Thanks for the explanation DaveWT