"New" install of 3.9, try to add a product, get:

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Message from webpage
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Error happened
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OK  
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Steps:
Upgrade from 3.8
REMOVE entire folder IIS Uses
REMOVE database
Copy files
Grant Permissions (Local machine, so don't care about security)

Takeown /f "c:\NopCommerce" /r /d y
icacls "c:\NopCommerce" /grant Everyone:(OI)(CI)F /T

Run Install, specify valid info
Rebooted server
Log in as Admin, go to Catalog/Products, get message that is Very unhelpful

If Ignore and continue, when try to save, from Admin\System\Log:
A generic error occurred in GDI+.
System.Runtime.InteropServices.ExternalException (0x80004005): A generic error occurred in GDI+. at System.Drawing.Image.Save(Stream stream, ImageCodecInfo encoder, EncoderParameters encoderParams) at ImageResizer.Plugins.Basic.DefaultEncoder.SavePng(Image img, Stream target) at ImageResizer.ImageBuilder.BuildJobBitmapToStream(ImageJob job, Bitmap source, Stream dest) at

Note item IS visible in Catalog\Bulk Edit
Note the permissions are very complete (Full trust to the Everyone group, including the Images folder and all subfolders)

Adding more permissions didn't help either:

icacls "c:\NopCommerce" /grant SYSTEM:(OI)(CI)F /T
icacls "c:\NopCommerce" /grant SERVICE:(OI)(CI)F /T
icacls "c:\NopCommerce" /grant IIS_IUSRS:(OI)(CI)F /T

Appears to be something with the handling of image, in particular images that don't yet exist

Re-installed yet again, with the sample data - Search then works
When I add a product (Fields filled:  Product Name, Short Description, Full Description, SKU), then failure starts (e.g. Search for new product crashes)

When edit within DB to match existing product (New Product ID is 46) w/ the following:

update product set UnlimitedDownloads = 0, MaxNumberOfDownloads = 0, RecurringCycleLength = 0, RecurringTotalCycles = 0, MaximumCustomerEnteredPrice = 0, BasepriceUnitId = 0, BasepriceBaseUnitId=0
Where id = 46
Insert into Product_Picture_Mapping (ProductID, PictureId, DisplayOrder) values (46, 76, 1)

Search and shopping basket now work (Though edit doesn't)

Would hope permissions aren't the issue, since I've run:
(IIS App pool user set to DefaultAppPool)
Admin Command Prompt:

Takeown /f "c:\NopCommerce" /r /d y
icacls "c:\NopCommerce" /grant Everyone:(OI)(CI)F /T
icacls "c:\NopCommerce" /grant SYSTEM:(OI)(CI)F /T
icacls "c:\NopCommerce" /grant SERVICE:(OI)(CI)F /T
icacls "c:\NopCommerce" /grant IIS_IUSRS:(OI)(CI)F /T
icacls "c:\NopCommerce" /grant DefaultAppPool:(OI)(CI)F /T
icacls "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files" /grant IIS_IUSRS:(OI)(CI)F /T
icacls "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files" /grant DefaultAppPool:(OI)(CI)F /T
icacls "c:\NopCommerce\Content\Images" /grant IIS_IUSRS:(OI)(CI)F /T
icacls "c:\NopCommerce\Content\Images" /grant Everyone:(OI)(CI)F /T
icacls "c:\NopCommerce\Content\Images\Thumbs" /grant IIS_IUSRS:(OI)(CI)F /T
icacls "c:\NopCommerce\Content\Images\Thumbs" /grant Everyone:(OI)(CI)F /T

Powershell:

dir "c:\NopCommerce" -recurse | Unblock-File

And attempted to create many of the folders probed:

mkdir "C:\NopCommerce\Administration\Views\Shared\EditorTemplates\App_LocalResources"
mkdir "C:\NopCommerce\Themes\DefaultClean\Views\Shared\EditorTemplates"
mkdir "C:\NopCommerce\Themes\DefaultClean\Views\Product\EditorTemplates\"
mkdir "C:\NopCommerce\Areas\Admin\Views\Shared\EditorTemplates"
mkdir "C:\NopCommerce\Areas\Admin\Views\Product\EditorTemplates"
mkdir "C:\NopCommerce\Areas\Admin\Themes\DefaultClean\Views\Shared\EditorTemplates"
mkdir "C:\NopCommerce\Views\Shared\DisplayTemplates"
mkdir "C:\NopCommerce\Views\Product\DisplayTemplates"
mkdir "C:\NopCommerce\Themes\DefaultClean\Views\Shared\DisplayTemplates"