The PST file of Outlook cannot be compressed

PST files are a specialized format for Outlook files and can only be opened with Outlook.

To import .pst file, follow these steps:

1.On the File menu, click Import and Export.

2.Click Import from another program or file, and then click Next.

3.In Select the file type you want to import from, click Personal Folder Files (.).pst)" and then click Next.

4.In Import File, click Browse to locate thePST file, and then click Next. If you know the path, type it in the box.

5.In Select a folder to import from, click the folder that contains the data you want to import.

If the folder contains subfolders, and you want to include the data from the subfolders during the import process, click to select the Include subfolders check box. If the import destination is the currently selected folder, click Import Project to Current Folder. Otherwise, click Import Project to Same Folder.

This will create a matching item in the selected destination folder.

6.Click Finish.

Find this file in the office installation directory, repair it with it, and then recompress it to shrink it. My original was repaired and then compressed to 500m, which took a long time. Of course, the premise is that you must clean up the mailbox of mail.

I've also encountered this question and I'm looking for an answer, and no one seems to be able to. :(

To save hard drive space, you can choose from a variety of options. PST folder, delete unwanted items, and then make the file smaller by compressing the file.

Note: When you delete unwanted items from each folder, it only moves them to the Deleted Items folder, in the same file. You must permanently delete them from the Deleted Items folder so that Outlook can delete items from the compressed files.

The compression process does not remove all the free space from the file. It retains either 16 kilobytes (KB) or 4% of the file size (before compression), whichever is greater.

To compress a file, the following requirements must be met:

The file must be 16 kb or larger.

The file must have at least 16 KB of space to be freed up since the last compression.

You can start Outlook file compression manually or run it automatically in the background.

Automatic compression in the background.

Due to storage. PST files are the interactions between your computer and your computer, and therefore, not in your computer's personal folder (.).PST) files may need to be compressed manually.

Automatic compression to idle tasks takes place in the background. The following conditions must be met for the background task to be executed

You must have Outlook running.

How to start PST compression manually.

On the File menu, click Data File Management.

Click the home folder (.) that you want to compresspst) file, and then click Settings.

Note: For Windows Vista. The default path to a PST file is Drive:

Users AppData Local Microsoft Outlook. For Microsoft Windows XP or Microsoft Windows Server 2003The default path to a PST file is Drive:

documents,settings user local settings application data Microsoft Outlook.

Click Start compression, click OK, and then click Close.

To save space on your hard drive, you can choose from a variety of .pst andRemove unwanted items from the OST file and make the file smaller by compressing the file.

Note: When you delete unwanted items from individual folders, this action moves them to the Deleted Items folder, which is in the same file as the items. You must delete items from the Deleted Items folder to permanently delete them so that Outlook can compress the files.

The compression process does not remove all of the free space from the file. It retains 16 KB or 4% of the file size (before compression) of the free space, whichever is greater.

To compress, .PST orThe OST file must meet the following requirements: The file must be 16 KB or larger.

Files must have at least 16 KB of free space since the last compression.

You can start Outlook file compression manually or let it run automatically in the background.

Automatic compression in the background.

Automatic compression can be done in the background like an idle task. For this task to run in the background, the following conditions must be met: You must be running Outlook.

1.On the File menu, click Data File Management.

2.Click to select the home folder, and then click Settings.

3.On the General tab, click Start Compression.

4.Click OK, and then click Close.

1.On the Tools menu, click to select the email account.

2.Click View or change an existing email account, and then click Next.

3.Click Microsoft Exchange Server, and then click Change.

4.Click Additional Settings.

5.On the Advanced tab, click Offline Folder File Settings.

6.Click Start Compression.

7.When the compaction operation is complete, click OK twice.

8.Click Next, and then click Finish.