# Unable to WGDOS to this accuracy **URL:** \ **Category:** Unified Model\ **Created:** [21 July 2026 13:08 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136 "2026-07-21T13:08:25Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![kqiu](https://avatars.discourse-cdn.com/v4/letter/k/6a8cbe/32.png) [@kqiu](https://cms-helpdesk.ncas.ac.uk/u/kqiu)\ **Post date:** [21 July 2026 13:08 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/1 "2026-07-21T13:08:25Z")
Hello, I’m experiencing a persistent **“Unable to WGDOS pack to this accuracy”** error with my suite u-dw943 for the task “Europe\_km11\_RAL3P3\_um\_fcst\_000”. This task has run successfully before, but because I had an issue with the archive and also with the recent MASS switchover, I stopped my runs and switched off the archive, but when I reran, i’m beening keep getting this **“Unable to WGDOS pack to this accuracy”** error. This diagnostic is essential for my simulations, so removing it is not an option. I have previously encountered this error, and I was advised to unpack so that I can at least examine it. However, after unpacking, I still get this error. ![Screenshot 2026-07-16 at 13.28.09 23.11.34](https://europe1.discourse-cdn.com/flex013/uploads/cms_support/original/1X/f9eac9890d669ca1d934c2e92c2960dd685bd372.webp) ---
**Author:** ![jonnyhtw](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/jonnyhtw/32/548_2.png) [@jonnyhtw](https://cms-helpdesk.ncas.ac.uk/u/jonnyhtw)\ **Post date:** [21 July 2026 14:26 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/2 "2026-07-21T14:26:08Z")
Hi there. Could you please let me know your username and which platform you’re running on? Thanks. Jonny ---
**Author:** ![kqiu](https://avatars.discourse-cdn.com/v4/letter/k/6a8cbe/32.png) [@kqiu](https://cms-helpdesk.ncas.ac.uk/u/kqiu)\ **Post date:** [22 July 2026 10:50 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/3 "2026-07-22T10:50:12Z")
Hi Jonny, Thanks!. I’m running it on Monsoon3, and my username is kexin.qiu.ext ---
**Author:** ![jonnyhtw](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/jonnyhtw/32/548_2.png) [@jonnyhtw](https://cms-helpdesk.ncas.ac.uk/u/jonnyhtw)\ **Post date:** [22 July 2026 15:13 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/4 "2026-07-22T15:13:27Z")
Hi Kexin, I see that the head of the trunk of `u-dw943` is at Cylc version 7 (it has a `suite.rc` instead of the Cylc 8 `flow.cylc`). According to the [docs](https://code.metoffice.gov.uk/doc/monsoon3/cylc.html) ‘_You will not be able to successfully run Cylc 7 suites [on Monsoon3]_’. Has your local working copy been upgraded to Cylc 8 (I can’t see inside your home directory)? Cheers Jonny ---
**Author:** ![kqiu](https://avatars.discourse-cdn.com/v4/letter/k/6a8cbe/32.png) [@kqiu](https://cms-helpdesk.ncas.ac.uk/u/kqiu)\ **Post date:** [22 July 2026 15:32 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/5 "2026-07-22T15:32:25Z")
Hi Jonny, I checked the cylc version of my local copy, and it is cylc 8.6. I’ve run this suite successfully on Monsoon3 before. ---
**Author:** ![jonnyhtw](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/jonnyhtw/32/548_2.png) [@jonnyhtw](https://cms-helpdesk.ncas.ac.uk/u/jonnyhtw)\ **Post date:** [22 July 2026 15:44 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/6 "2026-07-22T15:44:47Z")
Hi there. OK thanks for this. Can you please commit your local changes with `fcm commit` so I can update my working copy? Thanks ---
**Author:** ![kqiu](https://avatars.discourse-cdn.com/v4/letter/k/6a8cbe/32.png) [@kqiu](https://cms-helpdesk.ncas.ac.uk/u/kqiu)\ **Post date:** [23 July 2026 13:02 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/7 "2026-07-23T13:02:09Z")
Hi Jonny, I’ve done that. Thanks a lot for your help. Best, Kexin ---
**Author:** ![jonnyhtw](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/jonnyhtw/32/548_2.png) [@jonnyhtw](https://cms-helpdesk.ncas.ac.uk/u/jonnyhtw)\ **Post date:** [23 July 2026 14:37 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/8 "2026-07-23T14:37:07Z")
Thanks Kexin. I’m doing a test run now for just `20190101T0000Z`. ![image](https://europe1.discourse-cdn.com/flex013/uploads/cms_support/original/1X/974d1da63b0931fa5e15923aa2858375869bef8e.png) > … I stopped my runs and switched off the archive… What is the setting that you changed to disable MASS archiving? This isn’t clear to me from your [changeset](https://code.metoffice.gov.uk/trac/roses-u/changeset/361351/d/w/9/4/3/trunk) where you switched it off. Thanks Jonny ---
**Author:** ![jonnyhtw](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/jonnyhtw/32/548_2.png) [@jonnyhtw](https://cms-helpdesk.ncas.ac.uk/u/jonnyhtw)\ **Post date:** [23 July 2026 17:30 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/9 "2026-07-23T17:30:31Z")
Hi again Kexin. Turning off the packing (i.e. setting `packing=0`) for this field’s package, reinstalling the workflow, and then triggering the failed task allows the task to complete successfully. Alternatively you can just start again from fresh. The file that you need to change is `~/roses/u-dw943app/um/opt/rose-app-stashpack1.conf` illustrated here… ![image](https://europe1.discourse-cdn.com/flex013/uploads/cms_support/original/1X/509b40cde3aea8c7850601e9af2402491758210e.png) More information on reloading and triggering a failing task can be found (for example) [here](https://cylc.github.io/cylc-doc/stable/html/user-guide/installing-workflows.html#reinstalling-a-workflow). Cheers Jonny PS - Cylc 8’s capability to run Cylc 7-style suites won’t work indefinitely, although I don’t know exactly when this will be. E.g. on Monsoon3… ```auto $ cylc --version 8.6.5 $ cylc install . WARNING - Backward compatibility mode ON - support for suite.rc files will be removed at 8.7.0 INSTALLED u-dw943/run6 from /lustre/ehz2col/collaboration/home/users/jonny.williams.ext/roses/u-dw943 ``` ---
**Author:** ![kqiu](https://avatars.discourse-cdn.com/v4/letter/k/6a8cbe/32.png) [@kqiu](https://cms-helpdesk.ncas.ac.uk/u/kqiu)\ **Post date:** [24 July 2026 09:44 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/10 "2026-07-24T09:44:39Z")
Hi Jonny, Thank you so much for this. I think I probably found the problem because I changed the archive inside the Nested region conf setup. Just found out that when I did that, I also accidentally changed the number in the above section, radiation scheme time-step. And the STASH that keeps giving me an error is shortwave TOA. So this is likely the problem. I’m gonna try to see if this fixes the error. Best, Kexin ---
**Author:** ![jonnyhtw](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/jonnyhtw/32/548_2.png) [@jonnyhtw](https://cms-helpdesk.ncas.ac.uk/u/jonnyhtw)\ **Post date:** [24 July 2026 11:34 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/11 "2026-07-24T11:34:10Z")
Hi Kexin. > Thank you so much for this. No problem 😃. > I’m gonna try to see if this fixes the error. Sounds like great progress. All the best. Jonny ---
**Author:** ![system](https://europe1.discourse-cdn.com/flex013/uploads/cms_support/original/1X/1fd2411499ffcbc299fe756cd5cdf26e44956558.png) [@system](https://cms-helpdesk.ncas.ac.uk/u/system)\ **Post date:** [23 August 2026 11:34 UTC](https://cms-helpdesk.ncas.ac.uk/t/unable-to-wgdos-to-this-accuracy/2136/12 "2026-08-23T11:34:18Z")
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