As seen in a previous guide, those with a Mac can easily install MacOS from a USB stick using a free application called DiskMaker X. However, if the Mac should have problems or errors and it will not restart, with the aggravating circumstance that the recovery utility no longer works to reinstall the system (present on all Macs), before going to a service center we can create a USB stick for installing the OS X system also from a Windows PC, so that you can reinstall the system from scratch, restoring the correct functioning.
1) Things to know before creating the USB stick
One of the most important components to own is the Mac OS X DMG file, which you should always have a copy of or which you can download using unofficial links to search on Google (you can also find those updated to the latest version with relative ease) ).
Before showing you the programs with which you can create a MacOS bootable USB stick on Windows, I remind you that doing this type of operation could invalidate the product warranty, so we advise you to act only if the 2 years have passed since purchase of the Mac (so it is out of warranty).
Some recommended tools allow you to directly create the USB stick from the MacOS DMG, while others allow you to extract the content (so you can create a new ISO with the burning programs and then bring it to USB) or directly convert the DMG to ISO, so as to have the base ready to create the bootable USB stick for the Mac.
Having the MacOS DMG file and a USB stick larger than 16 GB, it is therefore very easy for a Windows PC to prepare a bootable USB stick to restore or reinstall MacOS using one of the recommended programs below.
2) TransMac
One of the best programs to use is called TransMac and it is available here -> TransMac .
Unfortunately this program is not free but you can use it for free for 15 days, which is more than enough time to create the Mac installation USB stick (it is better to keep it separately since in order to reuse the program you need to buy a license use).
From the TransMac program, started with Windows administrator rights (click on it with the right button and then on Run as administrator ) click with the right mouse button, in the left pane, on the USB stick (which will become bootable on the Mac) and choose the " Restore with disk image " option.
Click Yes when you receive the warning that the USB drive will be completely erased, go ahead and press the button with the three dots to choose the MacOS DMG file.
Finally, click the OK button to start creating the installation USB stick for the Mac.
Once finished we connect the USB stick on the Mac, turn it on and hold the option button, so we can select the USB drive to do a fresh installation of the OS X operating system from scratch.
Currently this is one of the most immediate and fastest programs to create a MacOS installation USB stick from Windows, so we recommend using it first in any case and to evaluate the alternatives only if the creation fails or is not effective.
3) DMG Extractor
Another program that you can use to create a MacOS installation USB stick is DMG Extractor, downloadable on Windows from here -> DMG Extractor .
Once installed on the PC, simply open the DMG file of your MacOS copy using the Open button, then use the Extract button to extract all the contents of the image file in a folder of your choice.
With the extracted content we will be able to use various programs to recreate the bootable USB stick in ISO format, widely compatible with numerous software to create bootable USB sticks.
First of all we create the ISO using one of the burning programs available in the following guide -> How to Burn CDs and DVDs for free .
We choose one of the recommended software and follow the procedure to create an ISO disc with the extracted data; once the ISO is created, we can add it to any USB stick using one of the programs recommended in this other guide -> Programs to burn ISO to USB .
This is undoubtedly the most complex and laborious procedure, let's leave it only as a last resort, since very little is enough to make mistakes when creating the key.
4) UltraISO
Another program that we can use to convert the DMG file to ISO and then create the USB stick is UltraISO, downloadable for a free trial from here -> UltraISO .
Once downloaded on your PC with Windows let's open it, confirm the use of the free version and use the conversion tool available under Convert (button in the bar at the top or in the Tools menu).
A new window will now open where you can enter the path of the DMG file in the top field, while the path of the new generated ISO image file in the bottom field; before confirming, check the item ISO Standard (.ISO) and then click Convert to start the conversion process.
At the end of the conversion, simply create the installation USB stick with one of the programs already recommended at the top, present in the guide here -> Programs to burn ISO to USB .
This is the intermediate method, to be used immediately if TransMac does not succeed in its purpose, since even in this case it may take a few clicks to create the Mac bootable stick.
