Problem with MacOS update 10.15.7 2020-001

Also had issues with this 10.15.7 2020-001 update. Here is what worked running an Imac 2013 from external SSD.

• When starting the update, still on black screen, it had a brief reboot.
• After that the Mac failed to load from SSD every time.
• As my internal drive is a clone the Mac was only starting up with the internal disk, and not recognising the SSD as target disk.
• Pressing option key wasn't working to select SSD disk.

What worked for me:

1. I unplugged everything connected to the Mac and plugged my SSD in a different USB (the closest to the edge)
2. Did a PRAM reset (once)
3. Switched on, loud startup sound and the Mac loaded my internal drive with the clone, then I shut down after loading
4. Switched on again and pressed option key (the SSD disk appeared)
5. After loading the SSD I noticed the update was still pending on Systems Pref
6. Shut down again
7. Switched on again to check it would load from SSD, and it did!
8. Performed the update with no problem after that

Hope this helps..

Make sure you have set the external drive as the default in System Preferences. See the apple support page I linked to see how to set the default boot option.

What I recommend you do is first re-install Catalina on the disk. Re-installing DOES NOT ERASE YOUR MAC. It just replaces system files and removes security updates released after the release of 10.15.7. To do that download the full Catalina installer from here: https://apps.apple.com/us/app/macos-catalina/id1466841314?mt=12

Then launch the installer and select the external drive that you are booting Catalina from - MAKE SURE you select the correct disk - or it will upgrade Mojave on your internal disk to Catalina. It will install and restart your computer. Then try updating again by following the below steps:

1. Download the update (either from the package or Software Update in Sys Prefs)
2. Wait for it to install and then asks you to restart
3. DO NOT restart - shut down computer MANUALLY and then turn it back on
4. Hold option key to MANUALLY go to the external disk where the update needs to be
5. See if you get that White Apple logo like you do when you startup, with a little bar that says some minutes remaining. EXAMPLE:

If you don't get the bar and logo described above, that means there is something wrong and the update isn't even working when downloading/installing before the restart. If you get the logo and status bar with the time remaining as described in step 5, and it stills shows in Software Update that the update needs to be installed, then it might just be a weird bug and takes a while to recognize that the update was successfully installed.

Let me know if there is any problem EVEN after doing what I described.

Hope this helps.

Cheers, Jack

Here is the workaround that is working for me:

1. Shut down your iMac
2. Before turning it back on, unplug all other external drives from your iMac except for your external drive that you boot from. Leave this one plugged in.
3. Turn on your iMac.
4. After the iMac boots up, plug your other external drives back in.
5. Everything should work now.

This isn’t an ideal solution but it works for now, and hopefully Apple will fix this issue soon.

This is part of what finally after 1,5 days trying everything saved me, too.

1. Deleted the system part of my SSD (so not the "xyz-data" volume, just the system volume
2. Installed disconnected everything else from USB, only leaving this SSD plugged, as said to the 1st port of my iMac close to the thunderbolts (or called 4th or whatever you want)
3. Installation successful, so I re-connected other drives.
4. Then, after a next restart, problems seems to re-appear, booting from internal. Disconnected everything again, shut down
5. SMC Reset (unplug from power, in case of desktop machines)
6. NVRAM Reset (alt-cmd-p-r on immediately after powering on, hand keep them pressed together until your Mac really chimes and starts another time (yes, our fingers might hurt, get prepared)
7. To be safe and avoid one more time booting from internal, pressed alt after that, to call boot-manager
8. In Finder, reconnected drives again
9. What happened then to me: Only the first port with system SSD delivered the used speed. The other three port were damned slow as a floppy disk (well, 20 MB/s, instead of 420-450 what I usually have on the other SSD or 15o on another 7200 HD)
10. Another restart, again, disconnecting all, and again resetting NVRAM
11. Now it's working, usb bus port speed seems to be fine again (checking now the last drive, my Time Machine Drive, which I can't check with Blackmagic disc-tool, cause it's read only)

What I avoid until any further update about this update:

• No Shut-Down, setting my Mac to sleep instead
• Ignoring this security update (well, I don't like to ignore, but anyway, I won't ride this ****-trip again

See another post with my system specs for more:

https://discussions.apple.com/thread/252193478

Download the Security Update Package here: https://support.apple.com/kb/DL2067?viewlocale=en_CA&locale=en_CA

Remember to download this on the external drive and to set your external drive as the default startup disk.

View this support page on how to do that: https://support.apple.com/guide/mac-help/change-your-mac-startup-disk-mchlp1034/10.15/mac/10.15

If this doesn't work, try to use a keyboard with cable. Sometimes the wireless ones cause havoc.

The Standalone Catalina Security Update 2020-01 is available now. May want to manually download attach the External Dive and execute the update pointing it to external drive for installation. See what happens.

Hi fototype (and anyone else)

I send this as a bug report to Apple again. I'd kindly ask everyone with the same or similar issue(s) to do the same (as logically the support and developer team does not automatically follow the threads here in this forum)

https://www.apple.com/feedback/macos.html

Takes you 3 minutes of your lifetime, and hopefully heals you from daily morning-gym unplugging and replugging devices ;-)

Cheers and stay tuned,

Phil

This is interesting. Cause I've seen lots of people having exactly this problem. Okay, Lets try to investigate, I start with my setup:

iMac 27" Late 2013 / 3,2GHz QuadCore i5 / 24 GB Ram / 1TB int HD.

System installed on internal HD: Catalina 10.5.7 (all previous updates installed

External Disks:

1. Crucial X8 2TB SSD (System disks, with that it all happened). Splitted into two volumes, one excl for system, apps, user, second for misc data storage. APFS formatted. System installed Catalina 10.5.7
2. Another Crucial X8 2TB SSD, 2 volumes. APFS
3. Drive USB HD 7200rpm, 6TB, 2 volumes, MacOS extended

Running on the fourth USB port via ext. USB 3.2 Hub

1. Seagate Backup HD 6TB, MacOS Extended, used excl. as Time Machine disk
2. WD My Passport HD 2TB
3. Midi/Music Stuff: Nektar GX61 Keyboard, Yamaha AG03 Mixer, Korg nanoKontrol Studio MIDI Controller

When installing the Security Update, I was running 10.5.7 (all updates installed) from the ext. Crucial X8 mentioned above. No issues for long time (or better said, never), everything working fine. The rest of the story is known ...

Anyone else fancy providing his setup to find out more...?

Hi ElkyOne,

I've also been experiencing this problem and reporting via these forums. Here is my configuration:

Late 2013 21.5"  iMac14,1 Quad-Core Intel Core i5 2.7 GHz. Internal HD is configured with Mojave (all updates).

External USB devices: 1TB OWC Envoy Pro EX (NVMe M.2) SSD with Catalina 10.15.7, WD MyBook (TimeMachine), Apple SuperDrive (when needed), and my UPS is also connected via USB.

When I had attempted to install the 2020-001 Security Update, my iMac failed to recognize my SSD upon restart -- it appears that the update was never applied. My iMac had restarted from the internal HD.

In order to get booted up again, I had to do the following:

1. disconnect all USB devices
2. connect my SSD to the first USB port (next to the Thunderbolt ports)
3. reset NVRAM (three "chimes" -- don't know if this was necessary, but I did it as a precaution)
4. thought about an SMC reset, but I did not (sometimes needed to reset USB power, etc.)
5. reconnected remaining USB devices

Been running normally from the SSD (w/o 2020-001 SU) as I was prior to attempting the update.

A solution that work for me. 2013 iMac 14,2. My iMac hard been functioning perfectly, even with 10.15.6 installed, till the fateful day I updated to 10.15.7. My fix was to remove the original HDD, with my SSD. That however is not an option for all. My external SSD however ( Samsung T5 ) is still not usable as an external boot drive until I did the following.

1. Buckup the external SSD
2. Shutdown your Mac
3. Restart, Hold down the Command +R on startup till the Apple logo appears, release keys
4. One in recovery mode, select Disk Utility
5. In Dish Utility select your external SSD
6. Select erase
7. Give the Disk a name, format OSX Extended (Journaled), and GUID Partition Table
8. Select Security Options
9. Move slider from fastest on the left, 1 tick to the right, this will erase and do 1 pass of zeroes.
10. Once the format is complete. Restart and follow normal Mojave install process.,
11. Worked for me, after many, many other attempts to fix the Catalina bug.

I totally agree to you, and don't see no need for any conspiracy. It is a bug, that was concerning really special constellations. What I figured out, it seems more and more that following combination COULD lead to the described Problem

• iMac, late 2013
• Catalina 10.15.7 installed and running on external disk (Crucial X8 2B SSD). I had the same system on my internal original Mac HD
• Installing the security update 2020-001, with included Safari Updates
• And, I think, this is by hardware quite interesting: More that one external disk (or maybe other USB devices too, in my case it was both)
• Some SMC, NVRAM reset might help (I did it, but I've done so much in a row, that this is hard to be proven as necessary or binding)
• More interesting: Even with all other disks unplugged, the iMac only accepts the external volume connected to the first port, counting from right to left, so just beside the thunderbolts)
• The other USB ports suffered after successful booting significant drop of speed of speed, down to 15 MBs on SSD drives
• This might especially explain the Time Machine problem, described as being slow. Same for me, when ran migration tool, was wondering, but I found the problem Wirth the affected slow ports when trying to work in Logic, and my instruments were loading like time travel to Floppy Disks ;-) Of course, this does affect massively the Time Machine restore time. It really becomes a time-wasting-machine ;-)

So my personal opinion, why there are quite a lot users around suffering this problem, but not really thousands of them: iMac 27 late 2013 is not used that often anymore. So there are two user groups:

1.) The ones just using this "old" iMac for casual stuff, it is still running, and yes, it is a stable and lovely machine (I work professionally in graphic design, animation, till 3D, so everyday on S,AE, PP, AI, INDD and Blender / Cinema 4D (yes this is a pain in the a** concerning rending of course, but I have good deals with render farms, and always on my main clients side (an agency) a lot of other Macs, so sometimes we just let them all share rendering). I'm working a lot with Audio, too, right now on a classical composition using BBCSO from Spitfire Audio, with some 30 tracks Dorchester, some clips of course, but this iMac is still a lovely working horse. Sorry lost my track, back tip the users (you see, I really love my old iMac beside other ones haha)

These casual users might have (if they have) maybe one external disks, but I think quite few using this as a system disk. I run 2 SSDs, three HDDs and Midi/Music equipment. But this is NOT the normal user on an 6-8 year old machine I guess, nope?

And even if - maybe nothing would have happened if my external System SSD would have been on this USBN port when doing the security update. Who knows? I won't try it, go of course ;-)

I'm working on Mac since early mid 90ies, and I really don't see any sense in these ideas. Apple users will update their systems on their own, they don't need to be forced to do, usually once you have a Mac, you'll stay (special uses e.g. switching to a windows Machine for better graphic card support in 3D worlds is another topic)

So: NO, it is just bad luck, to have this special iMac with this kind of setup running this security update. And maybe it was a rainy day, or you ate too much garlic, before, **** who knows 🤣

In case of any more questions, please fell free to ask on, I'm always willing to help, like all others around here too.

Cheers and all the best, will go on composing a bit. On my loved old iMac, who's running pretty stable on this "****** Catalina" system (I had no a single prob with Catalina all the time, don't understand everyone complaining about "Crapalina". And again, I am a power user (oh yes, I had one problem, a "pirated" plug in didn't want to run with Catalina in Logic. I don't care, 'cause I was just waiting to buy it, and there was no demo version. I'm a bad guy, I know. But I bought it, as anyway planned, so I'm a nice guy again 😇

Stay tuned 🤘😎

Phil

I managed to reset the NVRAM using the Terminal -- my iMac boots up in Mojave on the internal HD normally.

I erased my external USB 3 SSD, reformed it as HFS+ (journaled), GUID, and launched the latest Catalina installer (from S/W Update), and it began the installation process to the SSD.

However, when the iMac restarts to complete the installation, my iMac restarts in Mojave from the internal HD, and fails to complete the installation. Something is preventing the SSD from being recognized after startup. Once the desktop appears, the SSD shows up with the following, but doesn't complete the installation process:

No *real* answer here, just joining in with the problem. I got a similar setup (imac 2013 with external SSD it starts from) and got big problems with the security update, including a non-starting system sometimes, while it sometimes works. I tried too many things to recap here, what *seems* to improve the situation for me was to plug the SSD (Samsung T5 in my case) to an USB3-hub with it's own power supply. It *seems* something with USB changed and somehow when starting up the external SSD is not ready to do it's job. It's all wild guesses, I'm no real expert, but as there are not a lot of reports about the problem I thought I share it here. Hopefully someone comes with a proper explanation and fix.

No solution either, but reports start to pop up: Obviously we're not alone with this strange, erratic behavior:

https://forums.macrumors.com/threads/security-update-2020-001-for-10-15-7.2275352/post-29397181

...an update.

My iMac is configured with Mojave installed on the internal HD, and (had) Catalina installed on an external USB 3 SSD. I had been operating with this configuration for quite some time (months).

After applying the latest Catalina update, my iMac rebooted into Mojave, and absolutely refused to boot from the external SSD, even though it appeared as a System Startup Disk. After many failed attempts to restart, I erased the SSD and attempted a clean installation of Catalina. The installer proceeds right up until my iMac must restart to complete the installation. Then it restarts using my internal HD (Mojave).

It appears that booting from an external device has been comprimised by this update.