Hello. This issue has been reported to Micro Focus R&D, and they have stated the following:

''This issue was caused by the rebranding of the service name. In ALM v12.55, the service name is HPE Application Lifecycle Management, whereas the service name in ALM v12.53 is HP Application Lifecycle Management, so upgrading directly from 12.50 or 12.53 to 12.55 will result in a missing tray icon. The fix for this issue was implemented in patch 2.''

When the customer upgrades from ALM v12.50 or v12.53 directly to v12.55 Patch 1, Patch 2 is expected to run over ALM v12.55 patch 1.

Currently, they have suggested the following workaround to resolve this issue. Uninstall the previous version of ALM, then install v12.55 Patch 2 as a full installer. This will erase the 12.53 HP aspect of the files. We are currently waiting on more feedback from R&D to see if we can get a solution for this issue. Once I have received the feedback, I will update this post.