Working with Files

I cannot open a PDF file that contains an invoice or remainder. 

I cannot open a TIF file that contains an invoice or remainder. 

Acrobat Reader message appears: "The validity of the document certification is UNKNOWN. The author could not be verified." 

I cannot open a PDF file that contains an invoice or remainder.

To open a PDF file you need to have the Adobe Acrobat Reader viewer installed. You can install the viewer from  Adobe Acrobat Reader site.

I cannot open a TIF file that contains an invoice or remainder.

When opening the invoice/remainder for the first time, it is possible that no default viewer is associated to the TIF document. The following short instruction will help you to set up the documents viewing. When a window pops up asking whether you want to open or save the document, click on "Otevřít" (Open). 

After that, select "Vybrat program ze seznamu" (Choose a program from a list) and confirm by clicking on "OK" button.

Click on "Prohlížeč obrázků a faxů" (Picture and Fax Viewer) which will be set up as the default program for TIF documents opening.  Check the box "K otevření souborů tohoto typu vždy použít vybraný program" (Always use the selected program to open this kind of file) and click on "OK".

Now, if you want to open the document with invoices/remainders, it will open automatically by the "Prohlížeč obrázků a faxů" (Picture and Fax Viewer) application which is a part of Microsoft Windows XP/Vista operation system.

Acrobat Reader message appears: "The validity of the document certification is UNKNOWN. The author could not be verified."

In this case, the problem is caused by the 1st Certification Authority (1.CA) Root Certificate store setup. The setup is completed in the presets of Acrobat Reader by the "Úpravy - Předvolby" (Adjust - Presets) instruction. 

Select the "Zabezpečení" (Security) category in the left part of the "Předvolby" (Presets) dialog window; click on "Další předvolby" (More Presets) on the "Integrace s Windows" (Windows Integration) tag and set the required parameters:

Confirm by "OK" button and restart the Acrobat Reader.

If the problem persists, the 1st Certification Authority (1.CA) Root Certificate is probably missing in the certificate store of your operation system. This problem can be very easily solved: you just add the I.CA Root Certificates to the authorizing servers lists. The Root Certificates can be found at the I.CA site at http://ica.cz/Korenove-certifikaty.

Adding Root Certificates for MS Windows and MS Internet Explorer viewers

In order to install the certificates, you can use a simple user application which is ready at the above mentioned website. On its opening, the application will copy files with certificates, opening a "Guide to Certificate Import" (a part of MS Windows) for each of the certificate.  In several steps, the guide will prompt you to confirm your selection and install the certificate. All the options are automatic; do not change the default setting unless you have a specific request, and proceed by the "Další" (Next) button.

Adding root certificates for other operation systems or viewers

If you cannot use the above mentioned application, you have to install the certificate manually. At the certificates site, select "I.CA Root Certificate for issued SHA2 Commercial Certificates" and download the first item on the list that will appear (file named as DER). On downloading the file, go back to the initial certificates site, selecting "I.CA Root Certificate for issued SHA1 Commercial Certificate"; again, download the DER file. The import of both the files depends on the specific viewer; however, most often, you will find the options for the certificates administration in the settings. For instance, in Firefox viewer it is in the "Rozšíření - Šifrování" (Extension – Encryption) section; in Google Chrome, the same option is under "Pod pokličkou - Spravovat certifikáty" (Under the Lid – Manage Certificates), in Opera under "Pokročilé volby - Zabezpečení - Správce certifikátů" (Advance Options – Security – Certificate Administrator). Usually, you select Certification Authorities tag, download the required certificate using "Import" button and confirm that you trust the certificate to be imported. If you have any problems, you will find all necessary information in the specific viewer help.