judge had not paid sufficient deference to Cst. MacDonald’s
“ability to draw inferences and make deductions as a police
officer and as an expert in online cloud storage and internet
investigations”. He was satisfied “that the trial judge erred
in equating the lack of knowledge of the precise manner of
uploading/computer use and the inability to state the ‘chances’
that electronic artifacts or use of the user account would be
found” [at para. 136].
 I agree.
The trial judge’s errors
 As a matter of context, it is worth noting that the police
investigation did not contribute to the delay. Cst. MacDonald
testified that it takes NCMEC between 90 days to six months to
transfer the files received from the electronic service providers
to the designated foreign federal agencies. In this case, NCMEC
completed transferring files to the R.C.M.P. in December 2012.
After the investigative steps described above, Peel police applied
for the warrant on January 21, 2013 and executed the warrant on
January 23, 2013. This is not a case in which the lack of police
diligence allowed evidence to grow stale.
 Further, there is something more fundamental than stale-
ness at issue here. Even if he had been cross-examined shortly
after the files were uploaded to Skydrive, Cst. MacDonald would
have been unable to state the “chances” that artifacts would be
found during the search. Given his lack of knowledge about the
computer devices from which the files were uploaded and their
technical characteristics, he would not have able to quantify for
the court the “chances” that any particular artifacts would be
found. He would not have been able to say anything more defini-
tive than what he explained in the ITO:
When these devices operate on the internet, electronic artifacts are left
behind. These artifacts can be used to corroborate the information sent from
Microsoft. With the information at hand, it is unclear it is one person using
the account [information omitted]@ hotmail.com or two individuals. Further,
if it is in fact one individual it is not clear if the suspect is travelling between
the dwelling houses with a computer system and using the Internet service at
each house, or is using the computer system(s) that are already present at the
residences. Police wish to seize all computer system capable of operating on
the Internet in order to identify, collect and preserve any images on the com-
puter, as well as the electronic artifacts to afford evidence of possession of
child pornography. The further analysis of the computer system(s) will clarify
. . . what computer(s) have access to this Microsoft account .
 The fundamental point is that the assessment of reasonable
grounds does not depend on mathematical notions of probability.