MathType crashes when we convert equations in word documents through program using MathTypeSDK

We are using MathTypeSDK to convert equations in Word documents to Latex.

We created a windows service for the same and our service fails after converting 150 to 200 documents with following exception.

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

We can observe the following 2 errors logged in eventlog.

Faulting application name: MathType.exe, version: 2018.6.12.373, time stamp: 0x5b1fa308
Faulting module name: MathType.exe, version: 2018.6.12.373, time stamp: 0x5b1fa308
Exception code: 0xc0000005
Fault offset: 0x0008ad81
Faulting process id: 0x4f00
Faulting application start time: 0x01d430507a05db8f
Faulting application path: C:\Program Files (x86)\MathType\MathType.exe
Faulting module path: C:\Program Files (x86)\MathType\MathType.exe Report Id: b0b728d2-9b93-4b26-9cda-de4245305ec4
Faulting package full name:
Faulting package-relative application ID:

Faulting application name: MathType.exe, version: 2018.6.12.373, time stamp: 0x5b1fa308 Faulting module name: MathType.exe, version: 2018.6.12.373, time stamp: 0x5b1fa308
Exception code: 0xc000041d
Fault offset: 0x0008ad81
Faulting process id: 0x4f00
Faulting application start time: 0x01d430507a05db8f
Faulting application path: C:\Program Files (x86)\MathType\MathType.exe
Faulting module path: C:\Program Files (x86)\MathType\MathType.exe
Report Id: a37c08b1-b637-4ff6-aa24-537ebaab040a
Faulting package full name:
Faulting package-relative application ID:

We are able to catch the exception and when we mark the error for current document and proceed with the next document, the error continues.

What's the best way, how we can recover MathType and continue processing the equations in other documents. Any ideas? Thanks in anticipation.