My mid-2009 13" MBP has started freezing ...

[Sirolway]

Help! I've had a mid-2009 13" MBP since they were released & it's been great.
But in the last couple of weeks it's been freezing - not usually when I'm using it, but when I try to wake it I get a beach ball & login screen, but no joy.

I've booted off a Snow Leopard DVD & repaired disk permissions (it found a small number of issues & repaired them), but I'm still getting the problem.

What can I try to fix this?

I've not installed anything recently, it doesn't happen when any particular app is running (I usually close all apps & leave the MBP to go to sleep on its own), so I can't really see any obvious pattern

 

[simsaladimbamba]

How much available HDD capacity out of what complete HDD capacity do you have?

 

[Sirolway]

500GB drive, 80GB free...

Been about that for a while & only recently started freezing
Can't really figure it out.
I did run Sophos anti virus for the first time in a while. Perhaps I should uninstall that for a while?

 

[simsaladimbamba]

I did run Sophos anti virus for the first time in a while. Perhaps I should uninstall that for a while?

Definitely.
No need for that, check the What about sending files to Windows users? section in the following FAQ:

Mac Virus/Malware Info by GGJstudios
There are currently no viruses for Mac OS X in public circulation, only a handful of trojans and other malware, which have to be installed manually via entering the administrator password.
The only anti-virus you need to protect your Mac is education and common sense.​

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Have a look at Activity Monitor (Applications / Utilities /) and select All Processes and sort by CPU to see what the culprit may be.
Also check the "System Memory" tab to see what your "Page ins:", "Page outs:" and "Swap used:" are.

image below uses sorting by CPU as an example

Further reading:

Mac OS X: Reading system memory usage in Activity Monitor
Making The Most of Activity Monitor
What Is Activity Monitor (or How to Take Your Mac's Pulse)​

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[GGJstudios]

I did run Sophos anti virus for the first time in a while. Perhaps I should uninstall that for a while?

You should uninstall Sophos permanently. Sophos can actually make your Mac more vulnerable, and you don't need any antivirus software to protect your Mac.

Read this: Mac Virus/Malware Info, especially the section "What about sending files to Windows users?".

 

[Sirolway]

Uninstalled Sophos last night & the Mac is fine this morning. Too early to tell if that's fixed my problem, but it's a promising start ...

I'd read reports of a recent malware that only needs Safari's "open safe files after downolading" to be checked (the default setting) to get onto your Mac, so thought perhaps I should give the MBP a scan, as it had been a while.

http://isc.sans.edu/diary.html?storyid=10813


In terms of Activity Monitor, once the laptop has frozen, I can't get to Activity Monitor

We shall see whether I get any freezes now that Sophos is off my machine.
Thanks, as ever, for the excellent replies - what a community!

I'll post again if I have any further problem

 

[GGJstudios]

I'd read reports of a recent malware that only needs Safari's "open safe files after downolading" to be checked (the default setting) to get onto your Mac,

The first part of the Mac Virus/Malware Info link I posted provides details about MacDefender.