Has anyone had problems with portfolio files holding digitally signed documents?

[rmiranda-applikon]

When I create or browse such a portfolio file on my 64-bit Windows 7 system, it freezes (crashes). This still happens after a fresh reinstall of Acrobat DC. Some others on our company network have the same problem on similar Windows 7 systems.

Our IT folks scanned the system logs and see that the problem always occurs when the Acrobat pluging DigSig.api is being invoked somehow. Here is the log output:

Log Name: Application
Source: Application Error
Date: 25/01/2016 10:14:50
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: NLWS0540.biotechnology.local
Description:
Faulting application name: Acrobat.exe, version: 15.6.30119.36332, time stamp: 0x56740a62
Faulting module name: DigSig.api, version: 15.6.30119.36332, time stamp: 0x56740811
Exception code: 0xc0000005
Fault offset: 0x0007cac7
Faulting process id: 0x854
Faulting application start time: 0x01d15750d01810f4
Faulting application path: C:\Program Files (x86)\Adobe\Acrobat 2015\Acrobat\Acrobat.exe
Faulting module path: C:\Program Files (x86)\Adobe\Acrobat 2015\Acrobat\plug_ins\DigSig.api
Report Id: 1596da2e-c344-11e5-8b27-a0d3c120f1db
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004...
<System>
<Provider Name="Application Error" />
<EventID Qualifiers="0">1000</EventID>
<Level>2</Level>
<Task>100</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2016-01-25T09:14:50.000000000Z" />
<EventRecordID>12873</EventRecordID>
<Channel>Application</Channel>
<Computer>NLWS0540.biotechnology.local</Computer>
<Security />
</System>
<EventData>
<Data>Acrobat.exe</Data>
<Data>15.6.30119.36332</Data>
<Data>56740a62</Data>
<Data>DigSig.api</Data>
<Data>15.6.30119.36332</Data>
<Data>56740811</Data>
<Data>c0000005</Data>
<Data>0007cac7</Data>
<Data>854</Data>
<Data>01d15750d01810f4</Data>
<Data>C:\Program Files (x86)\Adobe\Acrobat 2015\Acrobat\Acrobat.exe</Data>
<Data>C:\Program Files (x86)\Adobe\Acrobat 2015\Acrobat\plug_ins\DigSig.api</Data>
<Data>1596da2e-c344-11e5-8b27-a0d3c120f1db</Data>
</EventData>
</Event>

I would appreciate any indication of the cause of the problem and/or a solution.

R. Miranda