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External drive back up failure

Just got a new iMac using Catalina - trying to set up an external drive for a time machine back up and I keep getting this message "POSIX reports: The operation couldn’t be completed. Invalid argument."

Then the disk disappears off the desktop. I first thought the external drive was faulty was I swapped it but it has done it again. Wow. this used to be straight forward. Any help would be appreciated?



iMac 21.5″, macOS 10.15

Posted on Jun 17, 2020 3:16 PM

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Question marked as Top-ranking reply

Posted on Jun 17, 2020 3:36 PM

Brentfletch Said:

"External drive back up failure: Just got a new iMac using Catalina - trying to set up an external drive for a time machine back up and I keep getting this message "POSIX reports: The operation couldn’t be completed. Invalid argument." Then the disk disappears off the desktop. I first thought the external drive was faulty was I swapped it but it has done it again. Wow. this used to be straight forward. Any help would be appreciated?"

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Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. updates), system configurations (i.e. for Ports) become manipulated, technically. So, reset the SMC and NVRAM. Your hard drive may not be being read promptly, so resetting these, all of the ports would be configured to how they should be..

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6 replies
Question marked as Top-ranking reply

Jun 17, 2020 3:36 PM in response to Brentfletch

Brentfletch Said:

"External drive back up failure: Just got a new iMac using Catalina - trying to set up an external drive for a time machine back up and I keep getting this message "POSIX reports: The operation couldn’t be completed. Invalid argument." Then the disk disappears off the desktop. I first thought the external drive was faulty was I swapped it but it has done it again. Wow. this used to be straight forward. Any help would be appreciated?"

-------


Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. updates), system configurations (i.e. for Ports) become manipulated, technically. So, reset the SMC and NVRAM. Your hard drive may not be being read promptly, so resetting these, all of the ports would be configured to how they should be..

Jun 17, 2020 3:23 PM in response to Brentfletch

How much free space do you have on your boot drive? Try to maintain a minimum of 20 GB so that Time Machine has adequate space for local snapshots.


Also run Disk Utility's First Aid on the TM drive. It will take 2-3 times longer than for a similar regular drive due to the complex ecosystem of file permissions and hard links. Patience is a must here.


If you eventually have to replace the drive I strongly recommend one of these: OWC Mercury Elite Pro


They are very reliable, have very good warranty and excellent customer support.

External drive back up failure

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