What are the OS reqs?

I could join fine, no problem.
I could even get work for CPU without issues.
But all WUs error out. Running the EXE directly tells me that "api-ms-win-core-path-l1-1-0.dll" is missing.

I'm on Windows 7 fully updated. If it does not support that OS, OK, but you probably shouldn't send out work for such systems, then.

Minecraft Java itself runs happily on the system.

I'm having same problem on my Windows 7 computer.

Have not tried this yet but I found this Microsoft article on some possible solutions / things to try:
api-ms-win-core-path-l1-1-1.ddl is missing

Most api-ms-win-core-path-l1-1-0.dll errors are related to missing or corrupt api-ms-win-core-path-l1-1-0.dll files.

More specifically, these api-ms-win-core-path-l1-1-0.dll errors can be caused by:

Invalid or corrupt api-ms-win-core-path-l1-1-0.dll registry entry.
Virus or malware infection which has corrupted the api-ms-win-core-path-l1-1-0.dll file.

Microsoft hardware failure, such as a bad hard drive, which has corrupted the api-ms-win-core-path-l1-1-0.dll file.

Another program overwrote the required version of api-ms-win-core-path-l1-1-0.dll.

Another program maliciously or mistakenly deleted the api-ms-win-core-path-l1-1-0.dll file.
Another program uninstalled the api-ms-win-core-path-l1-1-0.dll file.

In line with this, I would like to know more and I would appreciate if you can provide the following information:

Were there any changes you made before this issue occur?
What actions were you performing that resulted to this error message?
Do you have Lync add-on in Internet Explorer?

What are the troubleshooting steps you have done so far?

Moreover, we’ve got a few handy solutions for you to try:

* Use the System File Checker tool to repair missing or corrupted system files

* Create a test profile and see if the issue will occur. If not, this will give us an another angle to look at as it could be a corrupted profile.

Looks like Windows 7 is no longer supported by the current version of Python used to build the exe.
Project administrator has posted here about it.

Most likely we won't be supporting Windows 7.
Python itself doesn't support it anymore, so we can't keep our tools updated to build apps for it anymore.

I did some brief digging and I was unable to find anything in BOINC to restrict work based on windows version.
I'm doing some digging into whether Python 3.8 is capable of running what we need it to, but since we can't get security updates on it, I'm hesitant to say the least to deploy code with known vulnerabilities.

I would recommend installing a Linux distro if your machine is unable to run a newer version of windows. Microsoft themselves stopped updating Windows 7 around 5 years ago - I wouldn't consider it a secure platform anymore.

Update: I found a way to restrict it.
https://github.com/BOINC/boinc/wiki/AppPlanSpec

So I'll be implementing that.

I'll also implement the libc requirement I talked about in a prior post. But, I think back then I mistakenly said 2.17. We're really targetting 2.27 by building on Ubuntu 18.04.

Expect these changes soon. I recommend moving away from Windows 7 when possible.

Thanks