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While using the QuickBooks Software, you face an error message on the screen that will reflect the message that it could not connect to the server.QuickBooks Event Log Error 4 error that arises when the user launches (QBi) QuickBooks Integration Manager tool. The error message “Integration Manager could not connect to QuickBooks. Please make sure that it is open” is displayed to the user. Another error message that you may notice is “QuickBooks Event Log Error 4 – An unexpected error has occurred in “QuickBooks”: Returning NULL QBWinInstance Handle” under Windows Event Viewer. This is a Windows specific error that can also affect QuickBooks installed on the server. This can occur due to several reasons. Errors can be caused because of corrupted or damaged files. Apart from QuickBooks Event Log Error 4, can also occur due to some other reasons.
Symptoms of QuickBooks Event Log Error 4
Due to QuickBooks Event Log Error 4 for error accruing v faces following symptom are mentioned below
An active program window crashes with the arrival of QuickBooks error 4 in the event log.
QuickBooks frequently freezes on the arrival of the QuickBooks Event Log Error 4.
Windows become lethargic towards the inputs provided by the mouse or keyboard.
While running the same program, the system freezes again and again.
When running a QuickBooks application we face problems sometimes
.NET Framework 4.0 SP1 in Windows 7 is one of the reasons behind the QuickBooks Error event id 4.
What causes QuickBooks Event Log Error 4
QuickBooks Event Log Error 4 occurs due to several reasons that are stated in the below-given list:
A damaged or corrupted QuickBooks company file in the QuickBooks
Antivirus for virus damage the QuickBooks file
Inappropriately installed QuickBooks application.
Damage in the Windows registry.
Background application interference in the QuickBooks led to the accidental deletion of QuickBooks-related files.
Methods which can eliminate QuickBooks Event Log Error 4
Method 1: Updating QuickBooks to the newest version
First, login into QuickBooks as administrator.
Go to the Help menu to Update QuickBooks.
Mark all choices within the options tab.
Save the procedure and click on the Update Now tab.
When the updating of the QuickBooks is completed, Mark all choices within the options tab.
Restart the program to check the updated version.
Method 2: Using QuickBooks Install Diagnostic Tool
Download and run the QuickBooks Diagnostic Tool to check and repair the damaged window components
Go to the website and download the QuickBooks Diagnostic Tool and install the Tool.
Run it and click on the issues you want to solve.
Restart the system and take a look at putting in QB once more.

Method 3: Again Installing the QuickBooks properly
Clean Installation of QB by using the QB Clean Install Tool. First, we Uninstall QB, then rename the QB folders, and again reinstall QB. These processes are mentioned below with steps:
Uninstalling Steps
Open your system and then select the Windows + R keys to open the run box.
Type ‘control panel’ and opt for OK
Select the Programs & Features option.
Then go to the Programs list, and select QuickBooks and choose Uninstall.
Follow the instructions and uninstall it.
Rename the Folders.
Use ‘Windows Explorer’ to find all the hidden files or folders.
Rename every folder location.
Folder paths are as follows:
C:\programdata\intuit\quickbooks(year)
C:\users\the current user\appdata\local\intuit\QB (year)
C:\program files\intuit\quickbooks( year).
Installing Steps
First, go to the Windows Notification Area.
When you see antivirus, click on it and temporarily disable it.
If you are having issues then take a guide from your antivirus service provider.
After that, you are able to reinstall the QuickBooks.

Method 4 : Repair the .Net Framework
Download QuickBooks Component Repair Tool.
Save the tool after it is downloaded.
Close all the running applications, and open the QBInstall_Tool_v2.exe.
The process will start automatically, if it detects any problem, then restart the system.
Run the tool to resolve the error. However, if the error still occurs, then check if the windows are updated or not.

Method 5 : Install QuickBooks File Doctor Tool
By downloading the QuickBooks File Doctor, it can also be used to mend the QuickBooks error. The tool scans your file, cleans it up, and refreshes the location. Moreover, it additionally repairs the broken file. It can even resolve a number of network problems. To use the QuickBooks File Doctor tool, you would like to transfer and install QuickBooks Tool Hub on your system, obtaining the error:
Download the latest version of Hub.
Then, open the downloaded QuickBooksToolHub.exe file.
Install the application.
Now, proceed by agreeing to the terms and conditions.
After the software system installation finishes, open the Tool Hub by double-clicking the icon.
Run QuickBooks File Doctor
Within the Tool Hub, click on the file which has issues.
Choose QuickBooks File Doctor and select the file.
If you’re unable to search out the file, click Browse to go looking at the file.
Next, select the Check your file choice and click on Continue.
Now, enter the QuickBooks admin password details and click Next.
When the tool finishes the scanning and repair process, open the file. If the error persists, move to the successive means.