Software Troubleshooting · Topic 2 of 5
Windows Performance and Service Problems
Troubleshoot slow Windows performance, low memory, app crashes, failed updates, service errors, slow profile loads, limited connectivity and time drift.
- 4 min
- Use Task Manager to find a process that hogs CPU, memory or disk.
- Disable unneeded startup items and keep free disk space.
- A heavy page file means low RAM.
What it is
Not every Windows fault stops the computer from starting. Many are slow performance, an app that fails, an update that will not install or a service that will not run. The method is the CompTIA troubleshooting process: identify the problem, form a theory, test it, make a plan, fix it, verify and document.
How it works
Slow performance
| Check | What to look for |
|---|---|
| Task Manager | A process using high central processing unit (CPU), memory or disk |
| Startup items | Too many programs starting at sign in |
| Free disk space | A nearly full system drive slows Windows and blocks updates |
| Malware | Unknown processes, high network use, browser changes |
| Drive health | A failing hard drive with high disk use and slow reads |
| Updates and drivers | A pending update or an old driver |
Typical fixes are to end or remove the heavy process, disable unneeded startup programs, free disk space with Disk Cleanup, scan for malware, defragment a hard disk and add memory when the system runs out of it. A system that is slow only for one user may have a profile or application issue.
Low memory warnings
Windows uses a page file on the drive when physical memory runs short. Heavy page file use is slow. Close unused programs, find a program that leaks memory, increase virtual memory as a short fix, or install more RAM (random access memory) for a lasting one.
Application crashes and compatibility
Check Event Viewer for the faulting application and error code. Restart the app, install updates, repair or reinstall it, and try compatibility mode for an old program. Compatibility mode runs a program with settings from an earlier version of Windows.
Windows Update failures
An update may fail for lack of disk space, a damaged system file, a stopped service, a poor network connection or a conflicting driver. Free up space, run the Windows Update troubleshooter, restart and try again, and run sfc /scannow if files are suspect. A bad update can be uninstalled from Settings or Windows Recovery Environment (WinRE).
Service fails to start
Open services.msc and check the service status and startup type. The Dependencies tab shows services that must run first.
The Event Viewer System log usually names the reason, such as a failed logon account or a missing file. Set the startup type to the right value and start the service again.
Slow profile load and time drift
A slow sign in can come from a large profile, many startup items, a slow network path to a domain controller or roaming profile, or antivirus scanning. Check the network and startup items, and clean the profile.
Time drift means the system clock moves away from the right time. On a domain, wrong time can break sign in because Kerberos relies on close time agreement. Fix it by syncing with a time server in Date and Time settings, and if the clock keeps losing time at startup, replace the complementary metal oxide semiconductor (CMOS) battery on the motherboard.
Limited or no connectivity
Run ipconfig /all to look at the address. An address starting with 169.254 means Dynamic Host Configuration Protocol (DHCP) did not answer (see the Windows networking pages).
Check cables, the adapter in Device Manager, Wi-Fi, the Domain Name System (DNS) setting, and a proxy or virtual private network (VPN) setting. Release and renew the lease, flush DNS, or disable and enable the adapter.
Universal Serial Bus (USB) and device resource warnings
A USB controller warning or a device that is not recognised may come from a faulty cable, a power problem, a missing driver or too many devices on a hub. Try another port, reseat or replace the cable, update the driver and check Device Manager.
Quick wins come first: restart, check free space and Task Manager, then look at updates, drivers and malware.
What to remember for the exam
- Use Task Manager to find a process that hogs CPU, memory or disk.
- Disable unneeded startup items and keep free disk space.
- A heavy page file means low RAM.
- Event Viewer names the failing application or service.
- Update failures often come from low space, damaged files or stopped services.
- The Dependencies tab shows why a service will not start.
- A 169.254 address means DHCP failed.
- Time drift can break domain sign in. Fix by syncing, or replace the CMOS battery.
- Follow the troubleshooting steps in order and document the fix.
Common mistakes
Fixing before identifying. Changing settings at random can hide the real fault.
Blaming hardware first. Most slow computers have software causes, such as startup items or low disk space.
Restarting a service that depends on a stopped one. Check the dependencies first.
Not documenting. The last step of the process is easy to skip, and it helps the next technician.
Check yourself
Which tool shows the process using the most CPU right now?
Task Manager.
What does a 169.254 address on a client mean?
The client did not get an address from DHCP.
Why can a wrong clock stop domain sign in?
Kerberos needs the client and server clocks to be close in time.
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