Here is the procedure to turn off UFT logs.
UFT Logs
1. Close UFT
2. Go to UFT application installed folder (c:program files Unified Functional Testing or c:program files (x86) Unified Functional Testing)
3. Goto the sub folder bin
4. Open file
      log.config.xml
5. Find
    
6. Change it to 
    
More details on how to change logs settings can be found on HPE document [KM00467327][1]
If you want to disable all logging even errors check out HPE document [KM00468012][2]
  [1]: https://softwaresupport.hpe.com/group/softwaresupport/search-result/-/facetsearch/document/KM00467327
  [2]: https://softwaresupport.hpe.com/group/softwaresupport/search-result/-/facetsearch/document/KM00468012