troubleshooting

Recently I tried to update module "Microsoft.Online.SharePoint.PowerShell". It was updated OK, but:

Get-Module Microsoft.Online.SharePoint.PowerShell -ListAvailable | ft -a

gave me two modules So I tried to uninstall module with older version "16.0.8525.1200" and import module with newer version. It failed with error: "The version '###' of module '16.0.8525.1200' is currently in use. Retry the operation after closing the applications." 

Chef error:

DETAILS: THE RESULT OF [ CHECKOUT/TEST#1 ] WAS A FAILURE. VERSION '0.1.00XX' OF THE 'your_cookbook_name' COOKBOOK COULD NOT BE LOCATED ON THE [ your.chef.server ] CHEF-SERVER. PLEASE CONSULT THE ACTIVITY-LOG FOR FURTHER DETAILS.

Actually means "you cannot use version number with leading zeroes". I.e., e.g. instead of version number '0.1.0013'  try '0.1.13'

Problem:

Outgoing emails are not sending from one particular site, "immediate alerts" timer job stuck on some specific database, owstimer.exe consumes high memory on one SharePoint server.

You can restart SharePoint timer service (SPTimerV4), but after some time the same happens again. If you have courage to wait enough - you can see 100% CPU load and WFE server not responding.

If you are troubleshooting SharePoint search that does work in general, bot does'n work for a specific list or library
(i.e. Search box not working), 
and you already checked list settings -> advanced -> Search.. Allow items... 
and you already tried to reindex list and site, 
it's time to ensure that default item view form is in place and works ok.
Of not - just create a new display item form and make it default.