I don’t see a thread for useful system tools.
Yesterday I came across a tool called Monolingual. This free tool removes unnecessary language packs from macOS, and I recovered about 4gb of space.
There are a few tools around that remove this type of data. I use CleanMyMac. They can be really useful If you are short of disk space.
Not to be a horrible guy, but just be careful with CleanMyMac - sounds like one of those spyware/adware things that cause all sorts of issues!
Some of my favourite system tools/utilities off the top of my head:’
- Flux (now a little redundant)
- Coconut Battery (Mac and iOS battery health)
- Battery Health (Mac battery health, usage and so on)
- Caffeine (Stop your Mac from going to sleep)
- Daisy Disk (See how the storage space on your Mac is used)
- Duplicate Photos Fixer Pro (Use it to sort out duplicate photos - however be careful with these things!)
- Smart Convertor (for quick multimedia file conversions)
Flux is far from redundant. Night Shift is horrid in comparison.
I’d be super careful about “converters.” As a video editor, I’d like to point out a lot of convertors are not container changers, but compressor changers. What we want, generally, is as close to lossless, that is no loss of quality, as possible. Things like AVI/MP4/MKV/MOV are CONTAINERS and not CODECS (compressors, like H264/MPEG2/AVHCD/HuffYUV/etc). Most of these Container2Container type converters don’t just change from “AVI2MP4” they re-encode, that is to say, they RECOMPRESS. Compressing lossy video which is already lossy compressed is bad. If possible, it’s always best to merely change containers, assuming the codec is already one you’re happy with. If that isn’t possible, it’s better to convert lossy video to lossless and then re-encode to lossy video. It’s better than going lossy to lossy.
Hahha don’t worry, I only ever use it for quick conversions for low quality stuff. Got other stuff to use for proper stuff when I’m doing Final Cut projects 
Fair enough. It’s the kind of thing that I see everyone doing that just makes me shudder. A lot of people do it to HD source and ruin it with “conversion” which recompresses when what they really want is a simple container change.
I’m more of an Adobe gal, myself. Haven’t used Final Cut since the mid-2000s. Been Premiere since 5.1c in like 1998. I’m currently on CS5, but not by choice. I never wanted to give up 6.0, but no more rosetta meant no more 6.0. Sad days.
“Not to be a horrible guy, but just be careful with CleanMyMac - sounds like one of those spyware/adware things that cause all sorts of issues!”
I know what you mean. It does sound like a host of dodgy apps from the windows world. I have used it since about 2009 and it has always worked well with no sign of any associated malware
Hmm, lets have a look…
- iStat Pro/Server
- Growl/Hardware growler etc
- MacTracker
a few other which i think have been killed by their devs. ,will check and update if still under development otherwise i wont mention them by name.
I have a stack of utilities and hardly ever use them these days. Things are much more boring, I mean reliable, than they used to be.
Little Snitch - network monitor, tells you what apps & agents are trying to connect to and gives you the option to say no
Malwarebytes Anti-Malware - malware checker
TechTool Pro 8 - general disk & system utility
WhatSize - tells you where your disk space is being used
Disk Utility
Disk Warrior 4 - the ultimate in directory optimisation and repair
EtreCheck - awesome shareware utility that looks for bottlenecks in system performance
OnyX - Runs UNIX maintenance scripts, cleans log files and generally allows GUI access to many settings that otherwise require Terminal to change
Security Growler - a bit similar to Little Snitch but far simpler and free
Sloth - checks for open files, good for when you can’t eject a disk sometimes
TinkerTool - similar to OnyX
I use Magnet a lot. It lets you organise windows on your screen. I’m often working on two documents side by side and you can drag one to the left screen border and it resizes to take up half the screen, drag the other to the right and it resizes to take up the other half of the screen.
My list of useful Mac OS system tools:
Fluid - allows you to create web apps (e.g. I have created one for AppleTalk that I’m using right now)
Handbrake - for ripping DVDs
Seashore - MS Paint equivalent
TeamViewer - for remote control of home Macs when travelling
Caffeine - as above, to stop Mac from sleeping
MailPlane3 - Gmail app
SpaceGremlin - to find and free up space
I also use Crashplan, DropBox and GoogleDrive. And CarbonCopyCloner.
Listing off some of the common ones I use in the workshop…
SMART Utility (SMART Utility | Volitans Software) for displaying SMART attribute information and analysing drive performance to predict pending failures.
DiskWarrior 5 (https://www.alsoft.com/DiskWarrior/) for drives with damaged filesystems or directories. Chances are DiskWarrior can fix it without requiring an erase and reinstall.
Prosoft Data Rescue (https://www.prosofteng.com/data-rescue-recovery-software/) for recovering data from malfunctioning drives or volumes with damaged or missing directories.
Carbon Copy Cloner (https://bombich.com) for moving data between drives and performing pre-service backups.
coconutBattery (http://www.coconut-flavour.com/coconutbattery/) for checking battery runtime, health and performance statistics.
OmniDiskSweeper (Omni Labs — OmniDiskSweeper, OmniWeb, and OmniPresence - The Omni Group) for finding files and directories on volumes that are consuming excessive amounts of space.
Malwarebytes Anti-Malware for Mac (https://www.malwarebytes.com/mac/) for removing common malware variants from machines.
KeepingYouAwake (GitHub - newmarcel/KeepingYouAwake: Prevents your Mac from going to sleep.) a modernised version of Caffeine with better support for newer OS versions. Prevents a Mac from automatically entering sleep mode.
- CleanMyDrive 2 (from the creators of CleanMyMac) for quickly ejecting drives/external devices from the menu bar, and for cleaning unnecessary hidden ‘junk’ files from said devices (Mac App Store)
- Amphetamine, which is a prettier, more functional version of Caffeine/KeepingYouAwake (Mac App Store)
- Loading, which replicates the animated loading indicator found in the iOS status bar whenever an app on your Mac is connected to the network (website)
The rest of my arsenal has mostly been listed by others.