Run > MikTex Package Manager (Admin) -> install your packages You may have to select different server from the reporitory list (in my case the proxy only worked with http repo) Troubleshooting “Error: Windows API error 87: The parameter is incorrect.” close all instances of pdflatex, cmds, reboot to close all instances
This procedure will help us visualize if the problem is caused by some kind of software incompatibility that occurs when the message “Error, parameter 87 is invalid” appears. Several affected users, who experts say are also looking for a way to fix the problem, found out that even if they are in a clean state of shoes and boots, the error no longer occurs.
Notice what is documented on the MiKTeX 2.8 status page: “This release has reached End of Life status.” Installing packages from a remote package repository is easy. The current version might be 2.9. Actually I had the same problem with .9.2 right now. Luatex locked process was locking some of those files. After killing it I worked on it.
The “miktex” updater is now integrated into the “MiKTeX Console”. If you are installing the current version of MikTeX for a single user, Update (Admin) will not work, perhaps only the MikTeX console is used. In this case, go to “Updates” and change the “Install Less” value in the dropdown. Membership settings are hidden here. How do you start the Miktex console directly?
What type of error causes the program to display incorrect result What type of error causes the program to display incorrect result?
A significant error in a program is considered to be code that actually produces incorrect output/results, even if the program is run to completion. A program with an error in estimation may give the correct answer in many cases and the wrong answer in other cases. Logic errors are generally many types of errors that are difficult to detect and correct.
Why is there an API 87 error on MiKTeX?
The current version is 2.9. Admittedly, the root cause of API error 87 is that an open file is blocking your installation. It could be another financial app, two instances of the MiKTeX mobile app, or even a locked part of a previous running build.
Is the parameter not accessible, the parameter is incorrect?
Data Recovery – Disk Unavailable. The parameter is invalid. Typically, when experiencing the “Disk is not available, the parameter is considered invalid” error, advanced users first consider recovering data and files through this drive, and then resolve this error. Now you might be wondering:
What causes the parameter ” the parameter is incorrect “?
The parameter is invalid” is caused by file system corruption. In computing, a system is used to influence how data is stored and returned.

Ermias is a tech writer with a passion for helping people solve Windows problems. He loves to write and share his knowledge with others in the hope that they can benefit from it. He’s been writing about technology and software since he was in college, and has been an avid Microsoft fan ever since he first used Windows 95.