In Microsoft Outlook, the forms are user interface templates and codes that are used to display information stored in particular Outlook items. Each item, which you open in MS Outlook, uses a form for displaying information. Outlook stores local copy of every custom form in cache. When you store forums in MS Exchange public folder or in Organizational Forms library on Exchange Server, MS Outlook could use cached version of form. It helps Outlook to improve performance on client computer. In cache if any problem occurs with Outlook forms or the form cache, Outlook can not display items and you might not access data from PST file. This behavior of Microsoft Outlook renders all of your mission critical data inaccessible and cause serious data loss problems. At this point, you are required to carry out Outlook PST Repair to get your precious data back.

In a practical scenario, you might come across a number of issues when you try to open a new Outlook item or existing item in folder, the item can not be displayed. Additionally, you might encounter any of the below error messages:

"The form you selected could not be displayed. Contact your administrator."

Or

"The form required to view this message cannot be displayed. Contact your administrator."

Other times, MS Outlook may not show any error message but might open open default form instead of custom form or does not open the item.

Locate the form

When an item is created in MS Outlook, which uses custom form, Message Class field of item is set to name of form. When you open the item, Outlook examines Message Class field to decide what form should be used display item. Microsoft Outlook then conducts a search for required form. Outlook checks in following locations in specified order:

1) Memory: If you've another item open, which uses same form, Outlook already has form in memory and use that copy of form instead of leading new one.

2) Forms Cache: MS Outlook checks on your system to see if you've used a form before.

3) Current Folder: If form is not available in cache, Outlook examines to see if form was published to current folder.

4) Personal Forms Library: If form is not found in current folder, Microsoft Outlook checks in Personal Forms library.

5) The Organizational Forms Library: If form isn't available in Personal Forms library, Microsoft Outlook then looks into Organizational Forms library.

6) The Web Forms Library: If you created HTML based forms and publish them on Web server and enable Web services in MS Outlook, Outlook tries to find out HTML version of form.

Understanding forms cache size

By default, Microsoft Outlook sets a size limit of 2048 KB (Kilobytes) of forms cache. When you reach maximum highest disk space, which you set for form cache, oldest unused form is removed from cache.

Important information about forms and form cache is stored in Frmcache.dat file. When any problem occurs with this file, forms might get damaged and thus the PST file. In such circumstances, Outlook PST file may get damaged and you require Outlook PST Repair to sort out the issue.

In order to Repair PST file, Microsoft Outlook offers an inbuilt tool, known as Inbox Repair Tool or Scanpst.exe. This tool effectively repair most of the PST file objects in case if PST file gets damaged due to any internal reason such as CRC error, file header corruption or application malfunction.

But if the problem is due to any external reason such as improper system shutdown and virus infection, Inbox Repair Tool may not help you to fix the problem and you have to go for third party applications to Repair Outlook PST file.

These software are particularly designed to methodically scan entire PST file and Repair PST file along with all of its objects. These applications are quite easy to use and thus do not demand sound and prior technical skills to Repair Outlook PST as they come equipped with interactive and simple graphical user interface.

Stellar Phoenix Outlook PST Repair is the most advanced and effective software to ensure absolute recovery of damaged PST file in all possible scenarios of corruption. It repairs and restores PST file of Microsoft Outlook 2007, 2003, 2002 (XP) and 2000. This software is compatible with Microsoft Windows Vista, 2003, XP, 2000 and NT4 (SP6).