Hello,

I am happy to join this community as a R & RStudio user.

Currently I am using the following R & RStudion tools respectively:

**R version 3.2.5 (2016-04-14) -- "Very, Very Secure Dishes"**

**Copyright (C) 2016 The R Foundation for Statistical Computing**

**Platform: x86_64-w64-mingw32/x64 (64-bit)**

** RStudio: Version 0.99.903 – © 2009-2016 RStudio, Inc.**

Today I have a very strange problem with "solve()" function while computing inverse of Hessian matrix as follows:

```
out.H0_NONEX_TVClayton.JPM_CRSP.optimHess
[,1] [,2] [,3] [,4]
[1,] 244.17575 335.66923 39.06532 2059.5617
[2,] 335.66923 493.16159 49.87913 2864.6609
[3,] 39.06532 49.87913 6.88191 322.6178
[4,] 2059.56169 2864.66086 322.61783 23293.0391
```

solve(out.H0_NONEX_TVClayton.JPM_CRSP.optimHess)

NULL

Suddenly, solve function does not work on my RStudion.

I check this situation even when I try to compute the following easy computations:

```
1+2
[1] 3
> sqrt(4)
[1] 2
```

solve(5,2)

NULL

solve(5,10)

NULL

```
```

Someone could help me about this strange situation? Maybe I should change into new Rstudio version?

Best regards,