User wrote " Thank you, again! If I have understood correctly, you are saying that I need to upgrade all software programs to 64 bit before I try installing any OS upgrade? Is this what Go64 does?"
A - No. The Application called Go64 only identifies Applications ( Not drivers or extensions " that are 32 bit
User wrote " And you are telling me that because I am using OS 10.13.6 High Sierra I will still be able to use them prior to upgrading the OS?"
A - Yes as long as the computer is running High Sierra macOS 10.13 or if upgrading to Mojave macOS 10.14 - the old 32 bit applications should still work
User wrote " I do apologise for asking what may seem uninformed questions, but I am an artist, not a computer expert. It is essential that I upgrade my OS because my existing Photoshop no longer works, and my current OS is too old for the online (new) versions that Adobe now supplies. I have been using a very old Microsoft Office as well. "
A - It is best to ask every possible question before attempting an upGrade to a newer version of macOS this computer Qualifies to run. Easier to plan before upGrading than having to put the toothpaste back in the tube. Humour here 😃
User wrote " I still don't really understand why I was told ""Installation requires downloading important content. That content can't be downloaded at this time. Try again later ".
A - This is a tough one and will not speculate. From what I have seen and very often times related to below
There are factors:
1 - Like poor Wifi connection
2 - Slow wifi connection
3 - Too many other people downloading at the same time and Apple Severs are overloaded
4 - Software on the computer interfering with the download process including AntiVirus Software
Notation: Disabling the AV Software may or may not solve the issue. Removal of the AV Software may increase the chances of the download to perform as expected.
5 - Running behind a VPN which may increase Packet losses or corruption of the download
6 - If via wifi too many Other devices using the wifi at the same time reducing the Bandwidth to your computer.
7 - Best Results are via Ethernet Cable to Router
User wrote " Should I try doing some kind of intermediate upgrade in the first instance? And if so, which OS would you recommend? I would try to upgrade programs to 64 bit first as you suggested. "
A - If this is a " Mission Critical " or " Production " computer setup - the Gradual upgrade process may serve this machine better than jumping from High Sierra directly to Big Sur or Monterey. Remember, High Sierra was released in 2017 - 5 ears ago and much has changed in that timeframe including Hardware Demands with each newer version of macOS.
A - Presently, both Big Sur macOS 11 and Monterey macOS 12 are basically light years ahead of High Sierra. With that in mind, Big Sur and Monterey both seem to be tailored to SSD Drives and at least 8 GB RAM where 16 GB RAM is even better.
You are welcome
Do come back to the Apple Support Communities ( ASC ) in the future, if / or when additional questions may arise