Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

THE_BLUE's avatar
THE_BLUE
Icon for Cirrostratus rankCirrostratus
Aug 11, 2023

failed (UCS application failed; unknown cause.)

i'm trying to install new image but i face this issue failed (UCS application failed; unknown cause.), where in passsive i have install it with no issue
application delivery
security
Paulius's avatar
Paulius
Icon for MVP rankMVP
Aug 11, 2023

THE_BLUE At first glance without any information on your platform or what code you went from and what you're going to It seems like it might be a disk space issue. The following article might assist you in narrowing things down if it is disk space related.

https://my.f5.com/manage/s/article/K14403

  • THE_BLUE's avatar
    THE_BLUE
    Icon for Cirrostratus rankCirrostratus
    Aug 13, 2023

    the only different is /var is 60% use in active and 52% in passive. And i hav install the image in passive with no issue

    • Paulius's avatar
      Paulius
      Icon for MVP rankMVP
      Aug 13, 2023

      THE_BLUE Just because you can install it on the passive one without issues does not mean that will be the case for the active unit. I would attempt to get them to the same space amount first and after that I would ensure they both have the same amount of available code versions uploaded to them and installed in partitions. What I have seen in the past is that one unit would have images ready to install where the other would not which would cause a space issue. I have also seen each device have more paritions with than the other with code versions installed as well. Make sure they are exactly like for like and attempt the upgrade once more. Other option here would be to open an F5 TAC and see what they say.