SXA error when creating a site: Unrecognized Guid format

Question

I installed a clean Sitecore 8.2 Update 5 instance with SPE 4.7 and SXA 1.5.

I imported a tenant, a site, tenant-specific templates, media etc. from a colleague's environment. I don't think any items are missing, because another colleague used the same package with no issues.

When I try to add a new site to this tenant, I am getting this message:

The error in the SPE logs is not very verbose:

12380 17:14:51 INFO  Executing PsSitecoreItemProvider.Start(providerInfo='Sitecore')
12380 17:14:51 INFO  Executing PsSitecoreItemProvider.Start(providerInfo='Sitecore')
12380 17:14:51 INFO  Executing a script in ScriptSession ''.
12380 17:14:51 INFO  The script execution in ScriptSession '' completed in 1 ms.
12380 17:14:51 INFO  Executing a script in ScriptSession '$scriptSession$|mkb0u2wyy3eyw3pialwk0lwc|45d64bde-0494-4591-904b-bfeee42e1cc2'.
12380 17:14:51 INFO  The script execution in ScriptSession '$scriptSession$|mkb0u2wyy3eyw3pialwk0lwc|45d64bde-0494-4591-904b-bfeee42e1cc2' completed in 0 ms.
12380 17:14:51 INFO  Script item set to master:\system\Modules\PowerShell\Script Library\SXA\SXA - Scaffolding\Content Editor\Insert Item\Site in ScriptSession $scriptSession$|mkb0u2wyy3eyw3pialwk0lwc|45d64bde-0494-4591-904b-bfeee42e1cc2.
ManagedPoolThread #3 17:14:51 INFO  Executing a script in ScriptSession '$scriptSession$|mkb0u2wyy3eyw3pialwk0lwc|45d64bde-0494-4591-904b-bfeee42e1cc2'.
ManagedPoolThread #3 17:14:52 ERROR Unrecognized Guid format. Actual value: 
ManagedPoolThread #3 17:14:52 INFO  The script execution in ScriptSession '$scriptSession$|mkb0u2wyy3eyw3pialwk0lwc|45d64bde-0494-4591-904b-bfeee42e1cc2' completed in 776 ms.

What could be the reason of this?

EDIT: After following Alan's suggestion, I received the following in the output of PowerShell ISE:

VERBOSE: Cmdlet Show-NewSiteDialog - Begin
VERBOSE: Cmdlet Show-NewSiteDialog - Process
VERBOSE: Cmdlet Get-TenantTemplatesRoot - Begin
VERBOSE: Cmdlet Get-TenantTemplatesRoot - Process
VERBOSE: Cmdlet Get-TenantItem - Begin
VERBOSE: Cmdlet Get-TenantItem - Process
VERBOSE: Cmdlet Get-TenantItem - End
Get-Item : Unrecognized Guid format. Actual value:
At line:16 char:3
+         Get-Item -Path master: -ID $tenantItem.Templates
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Get-Item], FormatException
    + FullyQualifiedErrorId : System.FormatException,Microsoft.PowerShell.Commands.GetItemCommand

Answer 1

After Get-TenantItem cmldet was executed (we've got our tenant) script tries to access Templates field. It looks like it is empty or has some gibberish inside.

Please make sure that those fields are filled

All of them are heavily used by scaffolding scripts and cannot be empty. If you are not sure what should be the value of each of them, you can create a new Tenant and see.

To easily export a Tenant use this script: