Activity Monitor on Mac: Open It and Read the Five Tabs
When a Mac slows down, start by looking at what it is doing before closing anything. Activity Monitor lets you compare running processes with the Mac's overall CPU, memory, energy, disk and network activity, then check whether one deliberate change actually helps.
Open Activity Monitor and Set the Scope
Open Spotlight, search for Activity Monitor and open the app result. Apple documents Spotlight's search and opening controls in its Spotlight guide.
Before interpreting an empty or surprisingly short list, clear the search field and check the View menu. Apple's process-viewing instructions distinguish these useful scopes:
| View | What it includes | When to use it |
|---|---|---|
| All Processes | Processes across the Mac | Start here for an unexplained slowdown |
| Windowed Processes | Processes that can create a window, usually apps | Narrow the list to familiar applications |
| All Processes, Hierarchically | Processes grouped by their parent | Check relationships before stopping a helper |
Windowed Processes is a filter, not proof that background work has stopped. Restore All Processes when you finish investigating, and remove any search text before looking for a different app.
Read the Five Main Tabs
Choose the resource that matches the symptom. The table separates useful process columns from the whole-Mac information below the list, so a large cumulative total is not mistaken for a current speed.
| Tab | Columns worth starting with | Check alongside them |
|---|---|---|
| CPU | % CPU and CPU Time | System, User and Idle below the list |
| Memory | Memory | Memory Pressure and Swap Used below the list |
| Energy | Energy Impact and Preventing Sleep | 12 hr Power on Mac laptops, when present |
| Disk | Bytes Read and Bytes Written | The read/write activity graph below the list |
| Network | Sent Bytes and Rcvd Bytes | Data received/sec and Data sent/sec below the list |
Apple explains the CPU totals separately from individual processes. CPU Time describes accumulated processor time, so sort by % CPU when the question is what is busy now, rather than what has worked longest.
For memory, use the process column to find a candidate and the system summary to understand the context. The separate memory pressure guide explains the graph's colors and swap, without turning this into a second memory-cleaning procedure.
Apple defines Energy Impact as a relative measure, not watts. The 12 hr Power column is a longer view and appears only on Mac laptops, so its ranking can differ from the process using the most energy right now.
The Disk view concerns reads and writes, not the size of an app's files. In the Network view, distinguish bytes already transferred from the throughput shown per second. Neither total alone establishes a current bottleneck.
Sort Before Making a Change
Click a column heading to sort, then click its sort control to reverse the order if the largest values are at the bottom. Add missing columns through View › Columns, as Apple's process-viewing instructions describe.
Keep the same scope and sort order while comparing readings. Observe the Mac during the troublesome task, then again after that task ends, rather than comparing an idle desktop with an active export.
If an unfamiliar name rises to the top, use the process identification guide before stopping it. A position in the list identifies a resource user, not whether its work is unwanted.
Inspect One Process
Select a row and double-click it, or use the Info button, to open its inspection window. Apple documents both ways in the process-viewing instructions linked above.
Check that the selected process is still the one you intended to investigate, and compare its CPU and memory details with the main window. Use the hierarchical view when you need to see which parent a helper belongs to, rather than guessing from a shortened name.
Opening this window is an inspection step. You can close it and return to the list without ending the process or changing its files.
Quit First, Force Quit Only When Needed
Save work in the app if it still responds. Select the intended process, click the Stop button and read the confirmation, following Apple's Quit and Force Quit instructions.
Quit asks the process to end when it can do so safely. Force Quit ends it immediately, which can lose unsaved data and affect processes that depend on it. A process owned by another user may require administrator authentication.
Do not work down the list force-quitting everything with a high number. Try one known app, then compare the same tab and the Mac's responsiveness before deciding on another change.
Reopening an app lets you test it again, but it cannot guarantee recovery of unsaved changes lost during Force Quit. If the problem returns with a particular document or task, record that trigger rather than repeatedly ending unrelated processes.
Keep Diagnostic Reports for a Specific Question
If support asks for a process sample or spindump, use Apple's system diagnostics instructions. These are reports for investigation, not buttons that repair the selected app.
Record the affected app and the task underway when the problem occurs, then collect only the requested report. Keep the report private unless you have reviewed its contents and know where it will be sent.
Where Mole Fits
Mole Mac's Status dashboard and menu bar panel show CPU and memory usage, available disk space and network transfer rates, alongside top processes. Disk read/write rates appear in the disk tile while disk activity is high enough to show them.
Use that overview to notice a change, then open Activity Monitor for its process scopes, inspection window or diagnostic reports. The overview is not a replacement for Activity Monitor's investigation tools.
FAQ
Why Is a Process Missing From the List?
Clear the search field and select All Processes before concluding that it is absent. Windowed Processes excludes processes that cannot create a window.
Does the Largest Disk Number Mean the App Uses the Most Storage?
No. The Disk tab measures disk activity, including bytes read and written. It is not a ranking of the space occupied by each app's stored files.
Can Force Quit Undo a Slowdown Without Losing Work?
There is no such guarantee. Save first and try Quit, then reserve Force Quit for a known unresponsive process while accepting the risk to unsaved work.