When I try and run the Win 10 Anniversary upgrade (Windows10Upgrade28084.exe) I am informed that I do not have the 20 GBytes of free space on the C: drive required to proceed and the option to use an external drive is not presented:
As my laptop has only 90 Gbytes of available storage, with only 4 Gbytes currently free, obtaining 20 Gybtes free space by moving temporarily moving folders to an external drive is difficult.
Viewing the partitions with AOMEI Partition assistant I see that the Restore partition uses 20 GBytes of which 9.43 GBytes is free:
Is it possible to copy this partition to an external drive, delete it, expand the OS partition by 20 GBytes, run the Windows 10 Update, reduce the OS partition size by 20 Gbytes and then copy the Restore partition back (using AOMEI Partition Manager Standard)? I fear that the upgrade may require the Restore partition to be present in order to run OK.
Problem is that you can't merge partitions that are not next to each other.
Somehow you ended up with too many partitions, is that an upgrade from older windows on an OEM computer ?
You can backup recovery and delete it for sure. The upgrade doesn't need it - it is only needed to restore to factory state (whenever you bought it). As such you needn't restore it back at all until you want to do that.
As CountMike says you can't extend C directly - you need to shuffle the 450MB recovery partition to right hand side so the unallocated space you free up by deleting the last 20 GB partition is next to the C partition. Certainly you can do that with the free MiniTool Partition Wizard tool. Perhaps you can do it with Aomei - I don't know as I've not used that software.
Note that after the upgrade, you will have Windows.old present, similar in size to your existing Windows folder. This will automatically be deleted after 10 days. (You can also remove it using disk cleanup, but then you lost the option to roll back if you encounter problems).
Realistically, whilst it is possible to shrink Windows you'd be better off imaging what you have, upgrading the drive, and restoring your partitions from your disk image.
If it were me, I would get a 250GB USB external hard drive. They are now about $30. Install Macrium Reflect Free and make a Macrium Rescue CD/DVD/USB. Make sure the computer boots from the Macrium Rescue CD/DVD/USB. Image the entire hard drive to the external USB hard drive.
Macrium Reflect Free
Boot from the Macrium Rescue CD/DVD/USB, wipe the computer's hard drive, restore only the System (FAT32, 300MB), 450MB WRE (Windows Recovery Environment) partition, and then restore the OS partition to fill the rest of the space.
Just me, but I like to go ahead and run the utility under the restore menu to fix Windows startup problems after the restoration. Probably not needed, but doesn't hurt to do it anyway to make sure the BCD in the System partition has the right pointers to the Windows OS partition.
If you use the Media Creation Tool to make the USB install media....
USB Flash Drive - Create to Install Windows 10
...and boot from that to do the upgrade (you should still get the option to keep your files and apps) then it can ask for external storage to complete the install (apparently it has done this since the first RTM release)....Windows 10 Setup will examine your free storage space and note that your PC requires removable storage if there isn’t enough.
Followed suggestion of Bree and created a USB installer which does offer the option to use external storage when installing upgrade from there .... BUT ... after upgrade (and creation of Windows.old) on C drive, I started getting messages about MSVCR100.dll not found. mfc100u.dll not found from various applications, iTunes helper missing a dll. I downloaded Regclean Pro and performer a scan and optimise (no license needed), as this promised to fix such problems but after this the Win 10 Start menu stopped working. The start menu was visible from other accounts so Regclean Pro Optimise seems to have created a registry problem and not fixed the missing DLL problem. At this point I invested US$5 in the Start10 Start menu so I could do uninstalls etc. More scouting indicated that the problem of missing DLLs was related to to the Microsoft Visual C++ 2010 x 86 Redistributable, so I downloaded a copy of this, uninstalled the installed version (which had a higher version) and installed the download. This fixed the missing DLL problem and Start10 now gives the option to use the Win10 start menu, which seems to work. All this has taken many hours of work but I now have an updated Win 10, a usable start menu and no missing dll messages.
Glad you've made progress. Never use a registry cleaner - they are more trouble than they are ever worth.
They certainly won't fix missing dlls if the file is missing.
What is worrying is that running it may have caused other damage you don't yet know about...
