Can't update compiler tools CCS 8.3

Hi,

I have installed CCS 8.3.1.00004 (freshly downloaded from TI site, in order to try a start-from-scratch fix to the problem I describe here) and need to update the compiler tools. I have uninstalled every single other TI application I know of on my computer. I need to update the compiler tools to be able to work with some firmware we developed a few years ago. I also need to get this working with this specific version of CCS for reasons beyond the scope of this post.

When I run the Help>Install Code Generation Compiler Tools and select everything (or just the MSP430 stuff), I get, after a while, the following error:

An error occurred while installing the items
session context was:(profile=epp.package.cpp, phase=org.eclipse.equinox.internal.p2.engine.phases.Install, operand=null --> [R]com.ti.cgt.msp430.17.win32_root 18.1.8, action=org.eclipse.equinox.internal.p2.touchpoint.natives.actions.ChmodAction).
The action chmod failed - file c:\ti\ccs831\ccsv8\eclipse\downloads\ccs_update_5.5.0.00092.exe does not exist

I tried an install from scratch. No luck. I removed the workspace entirely. No luck. There is nothing in the directory specified (other than a saved directory containing empty 0, 1 and 2 directories, after trying the update). I tried to update CCS to the latest version (Help>Check for Updates>do all the things), and still have the error, though it has changed very slightly (see if you can spot the difference, though I don't think it helps):

An error occurred while installing the items
session context was:(profile=epp.package.cpp, phase=org.eclipse.equinox.internal.p2.engine.phases.Install, operand=null --> [R]com.ti.cgt.msp430.19.win32_root 20.2.5, action=org.eclipse.equinox.internal.p2.touchpoint.natives.actions.ChmodAction).
The action chmod failed - file c:\ti\ccs831\ccsv8\eclipse\downloads\ccs_update_5.5.0.00092.exe does not exist

After this second action, there is both a ccs_update_5.5.0.00092.exe as well as a ccs_update_8.3.1.00004.exe in the specified directory. This being windows, chmod doesn't make a lot of sense, but I have read, modify and execute access to this file.

My computer runs Windows 10, build 1703. I cannot disable antivirus, but I can monitor the antimalware packages running on the computer (Cylance, Defender), and they do not indicate that they are taking any action during this update attempt. I'm sure there's a log file in the c:\ti\ccs831 directory somewhere but I can't find it. The logs in ccsv8\install_logs only give information for the CCS install/update, not for the compiler tools, at least as far as I can tell.

ANY HELP would be awesome, I have run out of things to try! Should I just learn to compile using gcc? CCS is killing me. Thanks in advance.