How can I find what causes the spinning beach ball on my Mac?

Treat the cursor as a clue, not a diagnosis. Start by recording where it appears: only in one app, only while opening a particular file or doing a particular task, or in several apps. Note roughly when it happens and what changed beforehand, such as an app update or a newly connected peripheral. Avoid changing several things at once; otherwise it becomes harder to tell which observation matters.

If the problem seems limited to one app, try a different file or task in that app and see whether another app remains responsive. Apple suggests checking that the app is compatible with the installed macOS, checking for software updates, and considering recently connected peripherals or third-party plug-ins that could be incompatible. These are investigation steps, not proof that any one item caused the freeze. [S1]

Open Activity Monitor and select its Memory pane while the slowdown is happening, if you can. Look at the Memory Pressure graph and note its color or whether it spikes. Apple describes green as efficient memory use; yellow, red, or spikes are reasons to inspect whether an app is increasing pressure. If an app you do not need is contributing to pressure, quitting it may be a reasonable test. [S2]

Compare what you see during a slowdown with what you see when the Mac is responsive. One brief color change does not establish the cause, and a memory-pressure reading does not prove memory is the only factor. Record the app names and approximate timing rather than relying on a single glance.

Yes, low free space on the startup disk is one possible contributor to generally slow performance; an app needing more memory than is readily available is another. Apple points users to Storage settings to check or free disk space and to Activity Monitor to inspect memory use. Those are possibilities to check, not evidence that either one explains your particular beach ball. [S3]

If memory pressure looks unremarkable, that does not rule out an app-specific issue, storage constraints, or another cause. Check available storage, then keep observing the same pattern. Avoid deleting files just to run an experiment unless you know what they are and have decided they can be removed. These checks may help narrow the possibilities, but they do not identify every cause.

Use a short log and change one thing at a time. For example, a placeholder entry might read: “Time: [approximate time]. Scope: [one app / several apps]. Task: [what I was doing]. File-specific: [yes / no / unknown]. Memory Pressure: [color or spike observed]. Free startup-disk space: [amount shown]. Recent change: [app update / peripheral / plug-in / none noticed].” This is an example format, not a claim about your Mac.

First compare the affected app with another app or file. If one app is the pattern, check compatibility and updates, and consider whether a recently added plug-in or peripheral coincides with the issue. If several apps are affected, note memory pressure and available startup-disk space. After any change, repeat the same task and record what happens. A change in symptoms can help narrow the investigation, but it still may not prove a cause. If the Mac remains unusably slow, keep your notes and seek help from Apple Support or a qualified technician rather than making disruptive changes based on a guess.