Big Problems after update to macOS Sequoia

Ok, I had a chance to do a quick look at the report and below are my findings/suggestions.

• Little Snitch, as you know is an application layer software firewall. No third-party firewalls are required for macOS and Apple also provides two (that are disabled by default). My concern from my last reply is that the issue you are having may not be Mac-related, but network-related instead. Removing (or at least temporarily disabling) Little Snitch would rule out it being the culprit.
• DR Cleaner - macOS does NOT need any type of cleaner apps. Most of these tend to cause more issues than resolves them. In fact the following forum post should give you enough information about this app to remove it completely from your Mac: Remove Dr. Cleaner ASAP - Apple Community
• At the time of the report, your Mac is running macOS Sequoia 15.0.1. I suggest that you update it to 15.1.1.
• Finally, under the Diagnostics Information section, the lsd process crashed twice in the last 60 days. The lsd process stands for Launch Services Daemon, a core component responsible for managing app launching and document-to-app associations. Crashes in this process can lead to performance issues, such as high CPU usage and reduced battery life. However, with only two crashes, it should be monitored to see if they continue. If they don't reappear, you can ignore them ... but should they come back and often, further troubleshooting may be in order.

... so, the report came up pretty clean. However, see if you want to consider following my suggestions to see if they can help.

Not to worry, your English is far better than my German. ;)

I believe what you are seeing is the result of syncing some of your Mac's data to iCloud, which may be more network related and not with your Mac's recent macOS upgrade.

But, to rule out any issues, I suggest that you create an EtreCheck report, and optionally post it here if you need assistance with interpreting its results. If you are not familiar with EtreCheck, it is a free troubleshooting app, created by a valued forum member, that greatly aids in diagnosing difficult Mac issues.

Ref: Using EtreCheck to Troubleshoot Potential Mac Issues

Yes, I can actually read and write in German, but it is not my primary language.

Thanks for the images. Yes, this does appear to be a issue with your connection to the Internet.

• The first symbol, with the text "iCoud synchronisiert nicht" (iCloud does not sync), indicates that there is a synchronization issue between your Mac and iCloud.
• The second symbol, with the text: "Objekt wird geladen" (Object is loading), indicates the data transfers to/from iCloud is in-progress.

The issue now, is to try to locate where the bottleneck between your Mac and iCloud actually exists.

Let's start with does your Mac connect to your local network by Ethernet or by Wi-Fi? You responded to Barney-15E that your Mac is not connecting with a VPN, but is it still using some form of software firewall (other than Little Snitch)?

Regardless of how the Mac connects to the network, let's check which DNS servers it is using with the following command in the Terminal app: nslookup www.icloud.com

This will test the connection at the application layer and this is where client-server issues exist.

What you want to look for are the IP addresses listed after "Server" & "Address." These are either going to be local DNS servers on your home network, the ones assigned by your ISP, or commercial ones, like OpenDNS or Cloudflare. Regardless, they should be ones familiar to you. The result of this command should also provide you with the resolved DNS name of the iCloud server.

The other thing we want to check are all of the router hops between your Mac and iCloud to see if there are any excessive delays between them. We do this with the following command: traceroute www.icloud.com

Typically the first hop will be your local network router, the next will be your ISP's gateway. Each subsequent hop are routers between your ISP and iCloud. We are looking for either excessive times or complete failures.

It sounds like you’re having networking problems. Are you using any sort of Internet security or VPN software?Apple change the networking stack in Sequoia and useless garbage like those things break your ability to communicate over the Internet.

Thanks for providing the information. Ok, there is nothing wrong with your local wireless network or with your Mac connecting to it. That leaves us with the Mac itself.

At this point, I suggest that you contact Apple Support directly for further assistance with this matter. To do so, simply select the "Support" link on the lower left-hand side of this forum's web page. Good luck!

Before you try resetting either router, which one is performing as your network's "main" router? The FritzBox or the Extreme? If both are configured as routers, then you would have what is know as a "Double NAT" condition, which would not be efficient.

Thanks for clarifying that the Extreme is the only router providing the wireless network.

Once I understand which router is doing what, as far as routing, we can go on to recycling power to both of them ... and when we get to that stage, you will want to power both down (order doesn't matter.) Wait 3-10 mins, then power-up the FritzBox; again wait 5-10 mins to allow it to fully initialize. Finally, power-up the Extreme and wait for the Extreme's status LED to turn solid green.

Thanks for the images. That cleared up both router roles in your local network. I now see that your FritzBox is your "main" router, and the the Extreme is configured as a bridge. That would mean any network device, like your Mac, connected to either the Extreme by Ethernet or by Wi-Fi will be getting their respective IP addresses from the FritzBox ... and this is the ideal configuration for these two devices.

Now, if I understand your last post, even with the correct local network configuration, your Mac is still having issues ... correct?

If so, and after you have power recycled both routers, it issue still exists, then the next step would be to check the wireless connection between your Mac and the Extreme.

To start that, let's check the "quality" of that wireless connection. To do that we need to gather some information from the Wi-Fi icon on the macOS menu bar.

Hold down the Option key, and then, click on the Wi-Fi icon. A drop-down menu should appear with a list of items. What we will be interested in are the following values:

• Security = ?
• Channel = ?
• Country = ?
• RSSI = ?
• Noise = ?
• Tx Rate = ?
• PHY Mode = ?
• MCS Index = ?
• NSS = ?

Ok, I see a problem starting at the fifth hop. Once the trace leaves your local network, there shouldn't be any local network IP address along the way to the iCloud server.

Notice at hop 5, you are starting to see local IP addresses starting with 192.168.x.x. These should NOT occur unless there is something amiss with the path over the Internet. Personally, I have never come across this in my experience. FWIW, the "empty" hops are not necessarily an issue, but can represent a firewall is being used at that hop location that doesn't allow ICMP traffic (what traceroute uses.)

An excellent graphical tool, based on traceroute, is PingPlotter. I'll leave it up to you if you want to get it or not. The following reference is one that they provide to help you understand the results of a traceroute using their tool: https://www.pingplotter.com/wisdom/common-network-problems/

Then the issue could either be your local network ... that is, between your Mac & the Fritzbox, or with the Mac itself.

Let's start with your local network. You mentioned earlier that this issue is only with this particular Mac, and that this Mac is connected to an Apple AirPort Extreme base station via a wireless connection. In turn that base station is connected, by Ethernet, to the Fritzbox gateway.

Do you have the Fritzbox configured as a bridge, or is the Extreme configured as such ... or neither of them so that they are both providing routing services?

Do you know the exact model of your AirPort Extreme? (Is it tall or flat, for example?)