I upgraded my Ubuntu from 18.04 to 20.04 few weeks back. Since the past few days I am getting a very weird error on my system while booting up Ubuntu and I cannot access it. I can't understand what the error is but I have attached an image below. It's a dual booted laptop and Windows is booting up normally.
I know that editing the boot options line and adding 'nomodeset' solves the problem of my laptop during LiveCD mode, what I don't know is how to set it at boot up through Grub2 after I've installed Ubuntu.  So, my question is; how do I set nomodeset before I boot into Ubuntu?
Can cited works hold grammatical positions in sentences? Though I read this style quite often, I was recently told unambiguously by a reviewer that I was NOT supposed to use citations "as if they are objects in a sentence."  The following sentence is an example of what the reviewer considered unacceptable:       We analyzed the data using the Wilmerding method, guided by [12].   The references section might include the following:      [12] Smith, D., Marshawn, J., &amp; Devenshaw, A. 2011. Techniques and   Procedures for Applying the Wilmerding Method.  Prince Publications,   Inc, New York, NY.   The Wilmerding method1 is not a step-by-step algorithm that can be precisely followed as if by a machine, and thus [12] does not provide a step-by-step algorithmic description but rather guidance for using  the method. [12] is a relatively slim but authoritative textbook about how to use the Wilmerding method.  Within this question, for the purpose of discussion, I have intentionally put [12] in grammatical positions where it's an important element of the sentence and the sentence would make less sense without the reference.  Sometimes that seems to be the most efficient way to communicate the intended message.  Is using a reference as a grammatical sentence element like this OK?   Why might this not be considered acceptable?   Should I be rewording those sentences?  Is it enough of a violation to be worth passing the note on to authors of papers I review?   I considered posting this on  but it seems more specific to academia than general English usage, and the comment came from a content reviewer rather than a copy editor.   is related but it seems to be more about when to put authors names' in vs. outside of the parentheses in an APA-like style.   The numbered citation style (as opposed to following APA, for example) is required by the venue.  1: Fictionalized for the purpose of this discussion simple process builder failing with error "failed to access the value for variable because it hasn't been set or assigned" Note: This error might look like a familiar error but the   resolution mentioned in the  is not working in the below case and I am not sure why, hence posting this question.   Problem description:   I have a process builder on case object set to fire for every time new record is created. Criteria is set to 'Formula evaluates to True' with below formula: AND(NOT(ISBLANK([Case].AccountId)),ISPICKVAL([Case].Account.Active__c,'Yes')) With immediate action set to update custom field on the Case object. Custom field Active__c on the Account object is type picklist with two possible values 'yes' and 'no'.   Screenshots of the process builder:        Creating a case as shown in the below screenshot with very minimal details and especially not populating account details:    Throws below error:     The flow failed to access the value for   myVariable_current.Account.Active__c because it hasn't been set or   assigned.   Relevant data from log file:     22:14:31.0 (12479016)|WF_FLOW_ACTION_BEGIN|09L370000000FEJ 22:14:31.13   (13607478)|FLOW_CREATE_INTERVIEW_BEGIN|00D37000000H8hr|300370000008ZTl|301370000004weE   22:14:31.13   (15394571)|FLOW_CREATE_INTERVIEW_END|5525dfa7819c33f438ce3cef9b6c15c668d8ff2-3d11|Test   22:14:31.15 (15820974)|FLOW_START_INTERVIEWS_BEGIN|1 22:14:31.15   (16674702)|FLOW_START_INTERVIEW_BEGIN|5525dfa7819c33f438ce3cef9b6c15c668d8ff2-3d11|Test   22:14:31.15 (35470120)|FLOW_ELEMENT_ERROR|The flow failed to access   the value for myVariable_current.Account.Active__c because it hasn't   been set or assigned.|| 22:14:31.15   (35479812)|FLOW_START_INTERVIEW_END|5525dfa7819c33f438ce3cef9b6c15c668d8ff2-3d11|Test 22:14:31.15 (35517783)|FLOW_START_INTERVIEWS_END|Interview error.   Aborting all.|5525dfa7819c33f438ce3cef9b6c15c668d8ff2-3d11|Test   22:14:31.15 (35528335)|FLOW_START_INTERVIEWS_END|1 22:14:31.0   (35588898)|WF_FLOW_ACTION_ERROR|09L370000000FEJ|300370000008ZTl|Error   executing flow: test, FlowDefId: 300370000008ZTl, FlowVersionId:   301370000004weE 22:14:31.0   (35612585)|WF_FLOW_ACTION_ERROR_DETAIL|An unhandled fault has   occurred in this flowAn unhandled fault has occurred while   processing the flow.  Please contact your system administrator for   more information. 22:14:31.0   (35683203)|WF_FLOW_ACTION_END|09L370000000FEJ   URL to the complete debug log :  (Note: You can see from the log that there are no other workflow rules or triggers on the case object).  My analysis: When the first condition inside the AND expression is evaluating as false, why is it trying to evaluating the second condition to check the custom field on the Account object? It shouldn't right?  Any help?  EDIT: I am looking to solve this using option 'Formula Evaluates to True' only because I have other complex criteria like checking the day(Mon vs Tue and etc) of the case creation. For equal cost, why would you select the MacBook Air over the MacBook Pro? I can see that the 13" version of MacBook Pro and MacBook Air is same $1199, but the Pro is more feature-loaded than Macbook Air. Why would anyone buy MacBook Air? What's the catch in this?    I was thinking of buying a MacBook for development purposes, and worried if there's any problem in the Pro version, because it comes with more features (like more storage).  Edit:    Thanks for the answer guys, I bought a MacBook Pro a week ago and already loving it. Can I use a charger with more output amperage than the device needs? Windows 8 Setting an image on the login screen In Windows 8.1 when you log in there's the prelogin screen that has an image you can change, but then there's also the login (password entry) screen that as far as I can see is just a solid color.  How could I replace that with an actual picture? (ie, if I wanted a company logo to be displayed in the large space underneath the password entry box. Do I need a visa to transit (or layover) in the Schengen area? I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland Is there a word or phrase for someone who works hard at night and does not sleep? All the words or phrases I know for people who stay up at night merely describe the habit of not sleeping (e.g.: a night owl or insomniac)  I am looking for a word or phrase with an emphasis on working hard at night. These people work are different from insomniacs because they have no problem sleeping but they refuse sleep to work. They are different from night owl because they wake up early in the morning.  To give more context, suppose a nurse with kids who has a normal day life like most people and takes care of the kids but also works most nights in a hospital. I have some doubts regarding net run rate in the ongoing ICC world twenty 20 2014 event.It takes a while to read so please don't hesitate and give me a solution regarding this.    My doubt is that in match 12 of world twenty 20 2014(In Group Stage Last Match on march 21 2014) () Wesley Barresi of Netherlands hit a six when the team score was 187 while chasing Ireland score of 189, That take Netherlands score to 193.  If that is the case in match 17 between India and West Indies in match of super10 group (in ICC world twenty 20 2014 on march 23 2014) () while Suresh Raina (India) hit a four when the team score was 129 while chasing West Indies score of 129,That takes India Only To 130. why Only One run is added to the score in this match(match 17 on march 23 2014) while 6 runs are added to the score in match 12 on march 21 2014.  I don't understand the strategy behind this.Because if India's Score is taken as 133 then India's net run rate as of now(24 march 2014) will be 0.442(Runs Scored For 264 in 38.1 overs ) But Now it is only 0.383(Runs Scored For 261 in 38.1 overs ).As the net run rate plays an important role in the tournaments like this i am not very happy with this.  As being an Indian Fan now a days I look a lot in to net run rate as it has eliminated India in many tournaments including last ICC world twenty 20 2012.  Is There Any One who can clarify my doubts regarding the net run rate as i want to be sure of what was happening? What is the Python equivalent of static variables inside a function? What is the idiomatic Python equivalent of this C/C++ code?  void foo() {     static int counter = 0;     counter++;     printf("counter is %d\n", counter); }   specifically, how does one implement the static member at the function level, as opposed to the class level? And does placing the function into a class change anything? Rest mass of the photon Why is the rest mass of the photon is taken to be zero?  If rest mass of the photon is non zero, then it leads to infinite energy of the photon (by $E=mc^2$ equation) and there is a violation of conservation of energy. Is this a reason?  Also, is there any thing called the relativistic mass of the photon? Extract current viewing parameters from a 3D view? If $I = \langle 2\rangle$, why is $I[x]$ not a maximal ideal of $\mathbb Z[x]$, even though $I$ is a maximal ideal of $\mathbb Z$? How do I change the default wifi network that Ubuntu connects to on startup? There is an unsecured public wifi network in my range, as well as my own home WPA secured wifi that I want to use by default. However, on startup Ubuntu always connects to the unsecured one. Sometimes I forget to reconnect to the other one, which is very dangerous.   I am running a default setup of Ubuntu Destkop 11.10 with Gnome 3. I have looked under network settings but I can't find a 'default' option. Blender render crash when using subsurf modifiers. Difference between negative and positive temperatures written as absolute value or the negative integer? **In a chemistry class, students were learning about boiling point of various elements.Reuben has compiled a table that gives boiling points of each of various elements.  The lowest boiling point is of Element X: – 200 degrees Fahrenheit. The highest boiling point is of Element Y: 550 degrees Fahrenheit  Find the difference between the lowest and highest boiling point**    I know how to calculate the difference. -200 – 550 = -750.  I am not sure if the answer is written as a negative or positive. Isn’t difference in temperature always written as its absolute value? Will the answer be – 750 F or 750 F ?  Would greatly appreciate if you could explain what the correct answer is. How do you reset timers? How to maintain a file's 'last modified' date? Any way to control light halos in the compositor based on emission level? I am wanting to animate a row of LED lights. I have separated the LED lights from the rest of my object with the pass index/ID mask functions; currently all of my LED lights are on pass index #1.  What I want is to have a minor halo effect around the lights, but only when they are active. Currently, when I add a halo effect to my pass index #1, all of the LED lights have a halo effect regardless if the LEDs are emitting light. All LEDs are diffuse and emission shaders, so I can animate by controlling the mix amount between diffuse and emission.   Is there any simple way to have the halo effect created through recognizing light emission values, or will I have to just animate each LED as its own layer of compositing? I do not understand how dummy variables work in math.   Suppose we have:  $$I_1 = \int_{0}^{\infty} e^{-x^2} dx$$  How is this equivalent to:  $$I_2 = \int_{0}^{\infty} e^{-y^2} dy$$  How does this dummy variable system work?   Since $y$ is the dependent variable for $I_1$ How can $y$ itself be and independent variable for $I_2$  ??  Thanks! What spell slot count formula can I use to base my homebrew mechanic on?