Zoho Flow On-prem Agent Fails to Update and Won't Startup

(I also posted this issue under "requests".)

Started up my on-prem agent today, like I do every day, and found that two different instances of the app on two different computers are broken in the same way. Since it worked flawlessly yesterday with my computers not having been turned off, updated, etc., presumably this is the result of Zoho pushing some update today (both apps had "automatic upgrades" on).

In particular, when starting the app on Windows with its `startagent.bat` file, I first get a message to confirm I want to allow "Java Service Wrapper Professional Edition 3.5.51" to make changes to my device. This has never popped up before. After I allow this, the app starts up and returns the following output:

"C:\xx_Shipping\Zoho\FlowAgent\bin\wrapper.exe"
""../conf/wrapper.conf""
wrapperm | Configured log file set to 'C:\xx_Shipping\Zoho\FlowAgent\logs\wrapper.log'.
wrapperm | The "wrapper.java.additional.25" property was redefined on line #59 of configuration file: C:\xx_Shipping\Zoho\FlowAgent\conf\wrapper.conf
wrapperm | Old Value wrapper.java.additional.25=-XX:+UseG1GC
wrapperm | New Value wrapper.java.additional.25=-XX:+UseCompressedOops
wrapperm | Unable to write to the configured log file: C:\xx_Shipping\Zoho\FlowAgent\logs\wrapper.log (Access is denied. (0x5))
wrapperm | Falling back to the default file in the current working directory: C:\xx_Shipping\Zoho\FlowAgent\wrapper.log
wrapperm | Unable to write to the default log file: C:\xx_Shipping\Zoho\FlowAgent\wrapper.log (Access is denied. (0x5))
wrapperm | Disabling log file.
wrapperm | Permission check for Zoho Flow On-Prem Agent - START (SERVICE_QUERY_STATUS=TRUE, SERVICE_START=FALSE) -> PROMPT
wrapperm | Starting the Zoho Flow On-Prem Agent service...
wrapperm | Unable to start the Zoho Flow On-Prem Agent service - The system cannot find the file specified. (0x2)
Press any key to continue . . .

When I press a key, the app shuts down. The log file write error is inconsequential, but I don't know what to make of the rest of this as I've never encountered it. I tried restarting my computers, deleting** and redownloading the on-prem agents, but the same error persists.

**(By the way, deleting/uninstalling the on-prem agent is a real pain (at least on Windows). `FlowAgent\bin\uninstall.bat` does not work, and most files are in use as soon as your computer starts up, so they can't be deleted. If anyone is trying to remove it, turns out there's a phantom "\FlowAgent\jre\bin\javaw.exe" process that starts as soon as your computer starts, and you must force end the task with Resource Monitor in order to enable deletion of the entire agent. Don't know if this is a symptom of greater the issue at large here, but thought I'd mention it.)

To be clear, nothing changed on either of my computers between the time when the on-prem agents were working a day ago, and when I started encountering this issue.

This app and it is critical to the workflow at my business, so any advice or help resolving this issue would be greatly appreciated.

L

Update 1:
When I run `FlowAgent/bin/install.bat`, or check "start server" at the final stage of the installer .exe, I also get a slightly different error output from the agent like so:

wrapperm | Unable to install the Zoho Flow On-Prem Agent service - The specified service already exists. (0x431)
Press any key to continue . . .

Update 2:
I was lucky enough to have an older version of the agent on a third computer and found that it works without issue when I transfer it over to the problematic computers. As suspected, however, when this older version attempts to update, the entire agent breaks, just as observed initially.