HMRC Basic Paye Tools not working on iMac: 'Starting application' hangs

This has just appeared on the HMRC website but doesn't seem to work.

Basic PAYE Tools does not open after an Apple Mac operating system update

We are aware that some customers have been unable to open Basic PAYE Tools after updating their Apple Mac operating system (macOS). This issue is known to affect customers using the latest macOS operating system versions: 15 ‘Sequoia’, 26 ‘Tahoe’ and 27 ‘Golden Gate’.

The following workaround should enable you to access Basic PAYE Tools. These steps will need to be carried out each time you need to use Basic PAYE Tools:

1. Close Basic PAYE Tools completely and open ‘Terminal’ on your Apple Mac (select ‘Go’ at the top of your desktop and then Applications > Utilities > Terminal).

2. Copy and paste this command, then press Enter:

cd “/Applications/Basic PAYE Tools.app/Contents/Helpers/rti.app/Contents/MacOS”

3. Next, copy and paste this separate command, then press Enter:

./rti runserver 46729

4. Leave ‘Terminal’ open’ and then open an internet browser (for example, Safari) and copy and paste the following website into the address bar, then press Enter:

http://127.0.0.1:46729

Basic PAYE Tools will now show in the internet browser and can be used as normal.

Please do not open the normal Basic PAYE Tools application while this is running. Through the entire time of using Basic PAYE Tools in the internet browser, make sure you keep the ‘Terminal’ open.

Once you have finished using Basic PAYE Tools, press Ctrl+C in ‘Terminal’ to stop the server and you can close the ‘Terminal’ window.

 There are reports from other Mac users of problems with Basic PAYE Tools 26.1 on macOS Tahoe. 

In one February 2026 discussion, a former BPT developer suggested using Assistive Mode to a Mac user running Tahoe and BPT 26.1; the user later reported that this worked for them. This is an individual report, not an HMRC confirmation of a known Tahoe bug. (Reddit)

HMRC currently lists macOS 26 Tahoe as supported, including on Apple Silicon Macs, and the current BPT version is 26.1.26134.173934. (GOV.UK)

The first thing I would try is HMRC’s documented Assistive Mode. 

Open BPT once from its normal desktop shortcut or alias and close it. 

In Finder, open HMRC >> payetools-rti, then open bptshell-settings.ini with TextEdit. 

At the end of the file, add:

[General]

mode=assistive

Save the file and reopen BPT from the desktop shortcut or alias. 

HMRC says that BPT should then open in Assistive Mode in your browser. HMRC does not specifically describe this as a fix for a “Starting application” hang, but there is a user report of it resolving a BPT 26.1 problem on Tahoe. (GOV.UK)

I would not uninstall your existing BPT installation while investigating. HMRC specifically warns that uninstalling can result in loss of payroll data. 

The BPT logs are stored in ~/HMRC/payetools-rti/logs/ and may provide additional information about the failure. (GOV.UK)

HMRC’s current service-status page reports the service as fully available. 

It also contains an “Apple Support changes” notice, but that concerns Apple’s planned changes to support for Intel-based applications on Apple Silicon Macs from autumn 2027; HMRC says BPT will continue to operate normally throughout the 2026–27 tax year. 

It does not identify the “Starting application” problem as a current known issue. (GOV.UK)

So there is some evidence that other Mac/Tahoe users have encountered BPT problems and that Assistive Mode has helped at least one user, but there is not currently an HMRC statement establishing that the “Starting application” hang is a known Tahoe defect. 

Given that you experienced the problem on both Tahoe 26.7 and your current installation, Assistive Mode is the most directly relevant documented workaround to test before making more substantial changes.

I got the HMRC workaround to work after a number of tries. It seems the critical issue is to past in exactly as follows in bold below:

The following workaround should enable you to access Basic PAYE Tools. These steps will need to be carried out each time you need to use Basic PAYE Tools:

1. Close Basic PAYE Tools completely and open ‘Terminal’ on your Apple Mac (select ‘Go’ at the top of your desktop and then Applications > Utilities > Terminal).

2. Copy and paste this command, then press Enter:

cd "/Applications/Basic PAYE Tools.app/Contents/Helpers/rti.app/Contents/MacOS"

3. Next, copy and paste this separate command, then press Enter:

./rti runserver 46729

4. Leave ‘Terminal’ open’ and then open an internet browser (for example, Safari) and copy and paste the following website into the address bar, then press Enter:

http://127.0.0.1:46729/

Basic PAYE Tools will now show in the internet browser and can be used as normal.

I decided the work around was a bit weak so I made it easier to run with a downloadable Mac OS app that does all you need: https://payrollrti.uk/

its just doing what the HMRC guidance says in the background but no messing with consoles and port numbers.

Free to anyone who needs it since I needed it myself!

Ok now you have a new option at payrollrti.uk/beta

I got so frustrated with the poor support from HMRC so I’ve now built a version that runs the Linux download on the Mac

this may be quite brittle because of how I had to support it so let me know how you get on.

This should find your alternative db location. Let me know if it works.

I have the freeze issue on Macmini running sequoia15.8.1 I followed the HMRC workaround as you said but it made no difference.

However, by chance I clicked on the MacOS Unix Executable File (found in finder - BPT contents) and hey presto, it opened immediately via terminal (default).

Perhaps worth trying if like me you get frustrated!

Just to let you know I used this line instead and it worked fine.

cd '/Applications/Basic PAYE Tools.app/Contents/Helpers/rti.app/Contents/MacOS'

I don't know a fix, only the usual suspects and stuff I'd try out of desperation (all on the Mac).

• If you've got a VPN then turn it off.
• Try turning off the firewall on the Mac.
• Change your DNS servers to Open DNS or Google
• Check System Settings/Privacy and Security and make sure there isn't a permissions request waiting your attention.
• Hit F4 and make sure there's not a permissions request window that wasn't given proper focus so you missed it.
• Download Little Snitch and check which websites the App is trying to contact. Then ping them to make sure they are available.

Used Gemini to find a solution (this probably took half an hour of diagnosing). Pasting in the latest log file. It told me that (for me) the issue was with the front end application, govt servers were working fine. I did manage to submit payroll data to HMRC using a browser, all this since I updated to Golden Gate, was fine before.

I added something like this to the browser - http://127.0.0.1: <the port AI tells you your mac is using for the service>/?

It wont get the app working, but it is a workaround. It appears to be a common issue that should get fixed, especially if HMRC are not receiving payroll information :-)

HMRC Basic PAYE Tools will not work on OS15+ or 26.7.1

this after some time works for me

Close Basic PAYE open terminal

copt paste

cd "/Applications/Basic PAYE Tools.app/Contents/Helpers/rti.app/Contents/MacOS"

return

copy paste

./rti runserver 46729

return

leave terminal open

Safari

copy paste

Basic PAYE Tools - Home page127.0.0.1

it works

Certain misconceptions that persist regarding the relationship between Apple Computer and third-party applications, and services.

These misconceptions often arise when third-party products fail to function or meet user expectations.

Apple is responsible for addressing issues with its own services, applications, operating systems,

However, Apple cannot rectify user choices of third-party products  installed and used on their computers.

This responsibility lies solely with the third party to evaluate the performance of their products when used on an Apple Computer running the intended version of macOS.

How to contact an app developer

Ok I released that version as the main version based on testing with Linux and Mac. The website is also updated so hopefully more people who need it find it.

it’s so depressing that this was not done properly by HMRC. In general I’m really impressed by the government IT and online systems that have worked and do work well. This is an outlier that is a pain for us small businesses that use Macs.

anyway payrollrti.uk gets you a solution (for now and hopefully for longer)

Hi, I have the same problem, re-installed app, added rosetta, just in case.

Maybe a problem with .gov website?

I have checked my logs, found the following:

"2026-09-26 19:03:30.265 - Warning: Timeout waiting for response from web server."

This may explain the above, but nothing on the .gov website to say their web server is down......