how to recover outlook tasks that have removed/deleted due to PST file oversize or improper compression"
As this thread has been closed I cannot answer so I will share the solution here.
Next to "Help" on top there is a lamp "Tell me what you want to do". Click on that and type in "recover". You should see your deleted tasks now as you see your e-mails.
Hope I could help you. If you cannot understand completely answer this question.