MacBookPro Backup and Read/Write From/To Time Capsule Excessively Slow

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Using MacBook Pro (late 2011) 2.4GHi7 w 16GB mem 750GB HD partitioned 430GB Mac (42GB avail)/ 231GB Win (31GB avail) Journaled HFS+;
  running High Sierra v10.13.2 w Parallels Desktop 14 for Mac Pro v14.0.1
  Using 2 Airport Time Capsules 4th Gen v7.6.9, 3TB ea formatted AFP (the one being used for backup through Time Machine reports 923GB free through Disk InventoryX app)
  Time Capsules run under Airport Extreme 5th Gen v7.6.9.

Backups through Time Machine > Time Capsule are taking 6+ days (not sure of exact time; I'm having to cancel them).

Ran a few tests (under only MacOS; Windows not booted; Parallels not running); Wi-Fi turned off; Time Capsule connected to MBP via ethernet; running no other apps at time:

Test 1:  dragged 1.0 GB app file from MBP HD to Time Capsule to check write rate  RESULT:  Took over 25 minutes (approx 0.7 MB/s)
Test 2:  ran LAN_Speed Test to Time Capsule with 100MB packet size RESULT:  1.4 Mbps writing to TC, 1.7 Mbps reading from TC

Given the specs on the MBP and TC (1Gps ethernet port) the data transfer rates are excessively slow.

What can I do to fix this?  I can't leave my MBP tethered via ethernet to the Time Capsule for over a week to do a backup (need to take it to work daily).
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How full is the backup drive? Might you be running out of space? (Oh wait, you answered this.)
How big are your backups? I have noticed as my backups get bigger and bigger, just the compare and decide part of Time Machine takes forever. Might you have a lot of backups and a very big backup to run?
Also, have you run a Time Capsule disk check? Your AirPort Time Capsule should automatically performs a file system check on its internal drive during startup. To verify the drive, use AirPort Utility to restart your AirPort Time Capsule.  I will assume (since I do not own one) that any errors are reported to the Airport Utility.

You can try the demo of TM Error Logger ( and see if it tells you what kinds of errors you are getting. (the free trial gives you a 1 week usage.) Might give you a clue if there are errors happening.


Owen,  thx for the input.

I had previously restarted the Airport Extreme (not used in my tests with Wi-Fi disabled) and both TCs prior to running my tests.  No disk errors were reported on either TC and all of them (per my post) are on the current updates, as is my MBP.

I only have one large 417GB backup file for the MBP on the TC being used for backup (the other TC is used occasionally as a Network Drive to offload files when space becomes tight).  The TC being used for backup has over 900GB of its nominal 3TB capacity available.

I've restarted the backup after what seemed to be a hopeful increase in the throughput reported by LAN_Speed Test where after restarting the TC a second time it was showing a 100X improvement in the write time.  Unfortunately my enthusiasm was quickly curbed once I restarted the backup.  After running for over an hour, it has only backed up about 140KB of 197GB needing to be backed-up.  That's just a bit over 3MB per day which  is ridiculous.

I'm going to try the TM Error Logger now and report back.

Stay tuned (unless you or others have additional ideas in the meantime).

Any chance there is a problem with the Wifi? Have you done any testing of throughput on Wifi? Maybe this is a problem not where you think it is. Just curious.
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Fair question.  I had disconnected Wi-Fi prior to running my tests (see my orig Question for details).  So Wi-Fi wasn't a factor for this test but on a separate note, that is something I also need to troubleshoot separately.  It has gotten slow recently (this may all be network related; a common denominator).

I've downloaded the TM Error Logger and also connected a different USB SSD.  Since posting my last reply, this USB connected HD has backed up 36GB so far, hence orders of magnitude better throughput than through the TC which was connected directly to the MBP by a 6' ethernet cable.

I'm going to try to finish this backup this way then run some diagnostics on the TC with the TM Error Logger and go from there.

If no actionable errors are found, I'll try offloading the data from the TC (not sure how fast that will be but I may be able to dedicate another mac  have lying around to do that while i retain use of my MBP) and resetting it to factory and reformatting it.  Not sure if I do that if I should try reformatting it to APFS (I'll have to do some reading up) in preparation for a SSD upgrade I'm planning on the MBP (my understanding then is that the MBP would be using APFS which might then sync up better with the newly APFS-formatted TC).

Look forward to the results.



Using TM to backup to a USB-attached Backup Drive instead of to the Ethernet-attached TC produced a dramatically faster backup (approx 6-8 hrs to create an ~450GB backup).

Now that I have a current backup of my MBP, I'll try to:

first run a TM Error Logger diagnostic on TC1 and TC2 (hopefully getting some benchmark I can subsequently compare against)
then offload the contents of TC1 to other HDs
and follow some of the suggestions from current posts on how to resolve this issue (which includes reformatting the TC, hence the offload)

I'll report back in after I've made some progress (or if I get stymied)
The 5th Gen time capsule came out in 2013.  How old is your Time Capsule.  If it's 5 years old, that spinning disk may be starting to fail.  It's likely time to replace it.  Buy a replacement disk drive before every 3 years and rotate data to the new disk.  Keep the older disk around as tertiary backup, in storage.  Eventually, around 8-10 years, it gets taken apart for the magnets and destroy the disk platters.

This way, you'll have multiple backup disks, usually 3.  The newest one stays in heavy use.  The mid-aged (3-6years) one is kept as an occasional disconnected backup and the oldest one just stays in a drawer for archival recovery if you lose any older data.  When you buy the next one, destroy the oldest, much lower capacity disk.  That way you keep all your data on current media and also have it available for use on slightly older systems.  Disks are quite cheap now.  It doesn't make sense not to buy new ones every 2-3 years and copy everything to it.


Thx for the sensible input.

These are 4th Gen Time Capsules purchased in late 2012.  From my OP:
"Using 2 Airport Time Capsules 4th Gen v7.6.9, 3TB ea formatted AFP (the one being used for backup through Time Machine reports 923GB free through Disk InventoryX app)".

You may be on to something but my gut is telling me it's something to do with the communication protocol or formatting (this doesn't mean I should follow your advice regardless but in the short term it won't solve the issue if my hunch is correct; there are many threads out there with people having the same issue with TCs).
I would also suggest replacing it with SSD if you don't actually have too much data to save.  If you do, have a lot of data, those 8TB disk are quite inexpensive.  

Also, it's likely slow because the disk is starting to have a lot of S.M.A.R.T. errors, delaying access to the data.  It's time to copy the data out and replace the disk.  If your disk was very lightly used, you may be able to keep it for 10 years, but if it's been backing up daily or hourly, it's time to replace it.  Don't waste time trying to recover a failing disk.  It's only going to get slower, then fail.

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