There's a lot to like about OS X Yosemite, Apple's brand-new, super-powerful operating system of the future, but a quick glance around the software's official support forums shows that not all users are having a trouble-free experience. If you're struggling with strange bugs and quirks in Yosemite then these are the fixes you can try.
We've spent some time trawling through the unofficial and official message boards related to OS X Yosemite to try and pick out the most common issues that users are experiencing. Where applicable, we've also summarised some of the fixes that have been posted. Bear in mind that we haven't tested out all these fixes ourselves, so you proceed at your own risk, but they have reportedly worked for some.
Problems With Wi-Fi
Issues with Wi-Fi are dominating the OS X Yosemite discussions right now, so if you are having problems know that you are not alone. A whole host of potential fixes might help you out: this Reddit thread covers some advanced hacks covering kext editing, Bluetooth disabling, router tweaking and a complete reinstall of the Wi-Fi interface running on your Mac.
OS X Daily offers up a clearer and more condensed approach to tackling Wi-Fi woes step-by-step: essentially you need to erase all of your network plist files so that Yosemite will create them again from scratch. If that doesn't work, you can set up a new Wi-Fi network location with custom DNS settings. Check out the comments beneath the article for some other useful tips.
Problems With Bluetooth
Bluetooth: so simple and yet so troublesome. For a subsection of users, Yosemite is causing problems with Bluetooth accessories and connectivity. One solution proffered by iDigitalTimes is to disconnect all USB preferences, shut the Mac off for several minutes and then try again from the beginning. You may have to teach Yosemite about your Bluetooth accessories afresh instead of relying on what Mavericks has passed on.
Over on the official Apple forums, it looks like resetting your machine's PRAM (Parameter Random Access Memory) once or twice might fix the problem. PRAM is where all of the core information about your system is stored, and you reset it by booting up, then holding down the Cmd+Option+P+R keys right after you've hit the power button. When you hear the startup sound for the second time, you can let go.
Problems With Mail
We've seen several complaints of a Yosemite upgrade breaking the Mail application. The best course of action seems to be to double-check that your email provider settings are still correct and haven't been altered somewhere down the line without your knowledge. Uncheck the Automatically detect and maintain account settings tick boxes in Mail preferences (there are two of them) if necessary.
If your difficulties are restricted to a Gmail account that you're accessing via IMAP, then this article might be of use. It advises resetting your account both in Mail and in Gmail (through a Web browser) and then starting again from the beginning. As tedious and time-consuming as it might be, removing and then re-adding your email accounts is often the best way of getting around particular bugs that refuse to go away.
Problems with Notification Centre and Spotlight
A number of users are reporting issues with the Notification Centre, primarily Yosemite forgetting the preference settings after a reboot. If you follow the instructions set out in this MacRumors thread (apparently sourced directly from Apple Care) then you should find the problem is cleared up. Note that two reboots are needed at the end, not just one.
As for Spotlight, if you find that suggestions aren't working as they should, make sure that your language and region settings match up. You should also check that you're in one of the countries where the feature is supported. If you are, and your language and region settings match, then there doesn't seem to be a confirmed solution around just yet. You could try playing around with the Spotlight options in System Preferences, but otherwise you'll have to sit tight and wait for Apple to issue an update.
Problems With Lags, Graphics and Crashes
If you find OS X Yosemite slow to respond when waking up from sleep, there's a rather bizarre fix posted on Reddit that might clear up the problem for you. Apparently the issue is related to an automatic update that hasn't had chance to completely finish. Also from Reddit, if you're finding Yosemite prompts you to install iTunes 12 over and over again, downloading it directly from the official website rather than relying on the automatic updater should be enough to break the loop.
Graphical glitches relating to Photoshop seem to be common, and while a support rep confirms that Adobe and Apple are looking into it, there's nothing in the way of a fix or a workaround just yet. The same is true for many of the other graphics issues that have been reported, from Yosemite not identifying the right graphics card to weird colours and shapes appearing on screen. It looks like you're going to have to wait those ones out.
Performance-wise, Thorin Klosowski over at Lifehacker has a few workarounds that can speed up Notification Centre and improve poor graphics performance. They do involve disabling certain features but they will at least make Yosemite usable for you. In a similar vein, GottaBeMobile has some tips for improving performance, but having to turn off some of the bells and whistles in Yosemite just to use it isn't an ideal solution.
All of this is assuming the root of your problem lies exclusively with Yosemite and not something on the hardware side that has suddenly come to light. If you're running a 2011 Macbook Pro that's behaving erratically and throwing up graphics glitches then check out one of the longest troubleshooting threads we've ever seen on the internet. The GPU problem set out here might be exacerbated by Yosemite if it's pushing your hardware harder than Mavericks did.
Problems With Safari
All kinds of bugs are being reported with Safari, from sluggish performance to it refusing to load up at all. Some users are seeing an HDCP compliant error message appear when watching Netflix, and possible solutions include switching to Silverlight rather than HTML5 or unplugging display peripherals. Alternatively, you could switch to another browser until either Apple or Netflix get around to fixing the bug.
As for generally slow performance, there's always the usual route of deleting the cookies, cache and extension data that Safari has amassed during its travels. There's a chance that iCloud Drive is simply having teething troubles; disable the Safari option in iCloud Drive (head to the System Preferences pane to find it) to see if this has any effect.
Problems With Handoff
If the SMS functionality still refuses to work, you may have to disable then re-enable text forwarding. The old "turn it off and back on again" solution has become something of a joke in IT support circles but the reason it's so popular is because it works on a regular basis. Resetting Bluetooth and iCloud means the connection between mobile and computer has to be established again from scratch, which means there's a better chance of it working.
That's some of the major issues covered. The brave of heart can check out the main Yosemite bugs thread on MacRumors for a stack of other issues and bugs. If you're looking up details of your problem on the Web, be as specific as you can be with your search queries to help sift through all of the material that's out there.