Compact the personal folders (.pst) files in Outlook

To save space on your hard disk, you need to delete unwanted items from numerous PST folders and then compact these files to make them smaller.

Compacting process will not remove the entire free space from the selected file but it leaves 16 kilobytes or 4% of the file size before compacting (whichever is greater). In order to compact a file, a file must meet the following requirements:

  • File must be 16 KB or larger

  • File must have at least 16 KB of free space since the last time it was compacted.

Personal folders (PST) files that are not on your computer might require manual compaction. Automatic compaction takes place as an idle task in the background. The following conditions must be true for this background task to take place:

  • Outlook must be running.

  • Computer must not be engaged in other CPU-intensive tasks such as copying or downloading files.

In order to start manual compaction, follow the steps given below:

  1. On the File menu, click Data File Management

  2. Click the personal folders (PST) files that you want to compact and then click Settings

Note For Windows Vista, the default path of .pst files is drive:\Users\user\AppData\Local\Microsoft\Outlook.

For Microsoft Windows XP or Microsoft Windows Server 2003, the default path of .pst files is drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook.

  1. Click Compact Now, click OK and then click Close

Due to exceeding of PST file size limit of 2GB, PST files often get corrupt which makes them inaccessible. This can result in loss of some important data. Make sure you don’t fall into such situation and if in case you do, use an excellent Outlook repair tool, that will recover every bit of data from your corrupt, damaged, broken or inaccessible PST files.